Past Entrants

Past Entrants

2013 – Winner

Bosarge Family Education Center, 2013 ZNEBA Winner. Robert Benson Photography.

 

Coastal Maine Botanical Gardens

Bosarge Family Education Center

The winner of NESEA’s annual Zero Net Energy Building Award offers not only energy efficiency, but ideally also comfort, affordability, reliability, and elegance. Congratulations to everyone involved in this project. You are leading the charge on making sustainable energy practices the norm in the built environment.

Architects: Maclay Architects & Scott Simons Architects
Energy Consultant: Energy Balance
Mechanical & Electrical Engineer: Allied Engineering
Sustainability and LEED Consultant: Thornton Thomasetti
Structural Engineer: Becker Structural Engineers
Civil Engineer: Knickerbocker Group
General Contractor:  HP Cummings
Building Systems Fabricator: Bensonwood
Lighting Designer: J & M Lighting Design
Acoustical Consultant:  ACENTECH
Commissioning Engineer: Investment Engineering
Specifications: Lowell Specifications
Landscape Architect:  AECOM

Our winner in a climate with the most heating degree days

Read what the judges had to say…

“After much deliberation, this year’s judges chose to give the 2013 Zero Net Energy Building Award to Maclay Architects of Waitsfield, Vermont, who collaborated with Scott Simons Architects of Portland, Maine on The Bosarge Family Education Center in Boothbay, Maine. With a record number of entries this year, the judges had to identify a project that particularly stood apart from the others. The Bosarge Family Education Center, part of the Coastal Maine Botanical Gardens, did so in two major areas: building innovation and public impact.

 Not only did this northernmost building achieve net zero energy in a challenging climate with the most heating degree days, it was also pre-assembled primarily off-site. The building’s impressive airtightness levels are a testament to the builder, Bensonwood of Walpole, New Hampshire, the design team and the process.  It also brings great hope to the industry which has relied mostly on custom, site-built and intensively resourced structures in order to achieve such energy performance levels.

 The center was also recognized by the judges as a beautifully designed, natural light-filled building that echoed rural Maine forms in a crisp, warm and contemporary way, a structure that represents proudly the potential of what a net zero building can look like. The added flexibility to the interior spaces allows for the possibility of housing multiple occupancy conditions, something for which a low energy building is ideally suited.

Maybe most importantly, of all project submissions, this building represents the net zero building with the greatest potential public impact. As the only entry of the group and the first NESEA Zero Net Energy Building Award winner that is a public, non-denominational building, this building will serve as a showcase to many, wearing its credentials on its sleeve through “truth walls” and live energy monitoring.”

In the words of Maclay Architects…

“The Bosarge Family Education Center at the Coastal Maine Botanical Gardens was designed through a collaboration between our firm, and a local Maine architecture firm, Scott Simons Architects.

The client wanted to construct a new education center adjacent to their existing visitor’s center to serve as a model of sustainable, energy-efficient design. From the outset, the client outlined strict environmental guidelines with the goal of a LEED-Platinum, net-zero, beautiful building blending into the context of the surrounding gardens. The building was also to be an active teaching tool by outwardly demonstrating energy and resource conservation to visitors.  

This net-zero building is designed around a central open gallery: a gateway to the gardens. Two wings extend from this central core into the landscape, one housing administrative functions and the other flexible public space. Extensive glass enhances the connection to nature for occupants.

The pre-determined site was a confined parcel adjacent to an existing visitor’s center. Located in a valley, this site presented a challenge to the design team of maximizing the solar access critical to net-zero performance.  In addition, the client wanted to preserve as many of the large coniferous trees as possible. The site, along visitor’s central circulation path, allows the staff to be connected to the arrivals and departures of guests.

The orientation of the building allows for the use of passive solar strategies, optimizes the orientation of the roof-mounted PV and solar hot-water panels, and minimizes the impact to the existing site and trees.   Meters provide real-time energy data for all systems. Signage and a “truth wall” educate visitors about the buildings sustainable features. The highly insulated building envelope, high levels of daylight, and automatic controls optimize occupant comfort.

The client set forth a strict schedule for the project in order to preserve the experience of visitors during the high summer season. To meet this tight schedule a panelized construction system was used which allowed for off-site fabrication, minimized on-site waste, site impact and time. This project is the first net-zero project by our office completed utilizing a panelized system, and through careful thought and construction, it meets the air infiltration standards required for net-zero buildings. The panelized process offers a level of control and precision in a factory environment.  The envelope design and building assembly now established within the prefabrication parameters can be adapted for other projects.

The building design brings to life the mantra, “If a plant designed a building…”

OCCUPANCY STATEMENT

The Bosarge Family Education Center is occupied by office personnel full-time during working hours and is often used by visitors and for larger group activities on the weekends and evenings, especially during the summer season. The office staff in the building comprises 10-20 people depending on seasonal occupancy and daily needs. Events in the space are common and include 20-200 people. Therefore, occupancy is assumed at a higher number than just office staff.

 ≈ 300 Days of Occupancy

≈ 9,000 Person Days of Occupancy

COST OF CONSTRUCTION

Square footage of conditioned space – 8,200 SF

Construction Cost – $3,200,000

Cost/SF – $390/SF

MAJOR ENERGY RELATED SYSTEMS

  1. Building Envelope
    Sub Slab – R-20, 4” EPS rigid insulation
    Slab Edge Joint – R-20, 4” EPS rigid insulation
    Slab Perimeter – R-20, 4” EPS rigid insulaiton
    Above Grade Wall – R-40, dense pack cellulose in 11–7/8” I-stud cavity
    Roof – R-60, dense pack cellulose in 16” I-stud cavity

 

  1. Doors/Windows (U-value and SHGC):
    Windows: Low-e, tri-pane, argon filled, FSC certified
    0.16 U-value, 0.24-0.16 SHGC, 0.57-0.629 VLT
    0.154 U-value maximum
    Skylights (Type 1) 16 mm nanogel-filled polycarbonate inner layer
    Skylights (Type 2) Triple-glazed, low-E2, argon filled, 0.27 U-value
    Exterior doors, Low-E2, tri-pane, argon filled, 0.42 U-value

 

  1. Mechanicals Systems
    Space heating – Mitsubishi, single-phase air source heat pump
    Space cooling – provided by air source heat pump if needed
    Hot water – solar domestic hot water
    Ventilation – manual and automatically operated clerestory windows and skylights provide venting, ERV with automatic CO2 and airflow sensors provides all ventilation while recovering ≈ 70% of heat from exhausted air.

 

  1. Renewable Energy
    135 rooftop panels & 102 ground mounted panels
    45 kW peak power
    47,000 kWh estimated annual output

 

  1. Lighting
    LED, High-efficiency and Super-T8 throughout
    Daylight dimming and cutoff in classrooms in all public spaces, bi-level (manual on and auto off) in offices and other small spaces


To see the poster board presentation for the Bosarge Family Education Center please click here.

 

 

 

 

 


 

 

 

 

2013 – Judges Top 4
This year 13 applications were submitted for the Zero Net Energy Building Award. The judges had a terrible burden of picking just one winner, and after they did, they just couldn’t go without picking their top four zero net energy projects! Below are four of the projects submitted for the award that the judges couldn’t resist showcasing.

The Coons Family Residence

Clifton Park, NY

Here’s what Paul and Joanne Coons had to say about their home…

“Conducting an energy retrofit of our first home, a neglected 1852 Greek Revival, provided us with hands on experience and knowledge. We were looking for a new project and were alerted to a vacant historic 1830 farmhouse.  The front of the home faces south and a bike path that leads to our town center is located on the north side of the property. After walking through the dilapidated building we could see the hidden value of the structure. We envisioned it powered 100% by the sun.

 We set three goals for the project, to maintain the historic character, make the renovation sustainable and green and provide an energy efficient building.

 We started demolition only to find substantial insect, water damage and other structural issues that greatly increased the scope of work.  Our architect incorporated the newly found damage as well as other ideas from the Building Science Corporation book “Builders Guide to Cold Climates” by Lstiburek and ideas from the book “Prescriptions for a Healthy House” by Baker-Laporte, Elliott and Banta.

 We built new partitions inside the existing exterior walls using offset studs, allowing us to increase the insulation, as well as provide a thermal break. The new wall cavities were filled with approximately 8” of closed cell foam.  After replacing the second story roof structure (inadequate for the expected snow loads) we filled the rafter spaces with closed cell spray foam, covered the decking with a recycled rubber roof underlayment, 4 inches of Styrofoam insulation, and finally a standing seam metal roof.

 The design required us to preserve the existing room layout and south facing facade of the building. We renovated the facade by reinstalling wood siding, rebuilding the porches, existing double hung windows and wooden storms. In addition, we installed magnetic interior storm windows over the existing windows to increase their energy efficiency.

 Care was taken in choosing systems and products for energy reduction as well as local sourcing to reduce our construction and operating carbon footprint.

 Mechanical systems include a 3 ton ground source heat pump, a heat recovery ventilator and a whole house dehumidifier. Renewable energy is provided by pole mounted 8.4 kW photovoltaic (PV) and solar hot water (SHW) systems in the rear yard. We located the PV and SHW systems separate from the structure to maintain the historic facade of the structure.

 Interior work include American Clay finish over all walls, a milk based poly whey coating for all exposed wood finishes, paper stone counters and a local Amish cabinet maker crafted oak cabinets. 

The project met our three goals! We received the 2011 Town of Clifton Park Historic Preservation award and Town Conservation Easement, earned LEED Platinum and NAHB Certified Green Building Emerald awards and a NYS Energy Star rating. For the first year the local utility paid us for our excess electricity. We are now using the excess carbon free energy generated to power a 2012 Nissan Leaf and a 2012 Toyota plug-in Prius to help cover our transportation carbon footprint.”

Occupancy Statement:

The building, 4 Balsam Way has been continuously occupied by at least 2 persons since we moved in January 2011 to now, November 2012.   For the first 6 months we had a teenager living with us while she went to school locally. In the almost two year period, with an exception of two weeks this last summer and an occasional overnight visit to our families we have lived here continuously.  One occupant is retired and home most all day and second occupant is a school teacher and works 10 months per year.  Person days of occupancy = 1485.

Cost of Project and Square Footage of Conditioned Space:

The building has 2134 sq. ft. of conditioned space. The house construction costs were approximately $288,000 (minus barn, driveway, landscape, design and legal fees) or approximately $135 per sq. ft. (including PV, GSHP and SHW).

Building Envelope

Slab

  • Sub slab: dirt crawl spaces with two inches of Styrofoam under a plastic liner conditioned mechanical space basement with Anvantech flooring over two inches of Styrofoam and Patton polyethylene sheets
  • Slab edge: NA

Walls

  • Foundation wall design: existing, R-40 (rater indicates R-15) 8“ of closed cell foam over  plastic wall liner with offset steel studs and covered with paperless drywall addition, R-20 (rater indicates R-23) 8“ of sprayed closed cell foam over continuous plastic wall
  • Above grade wall design: existing, R-56 (rater indicates-47) offset wall studs with 8“ sprayed closed cell foam addition,  R-52 off set wall studs with 8” of closed cell foam

Roof

  • Flat attic: NA
  • Cathedral ceiling design:  existing, R-72 +/- three by four rafters joined with new 8” rafters, the resulting cavity filled with closed cell foam, and then four inches of Styrofoam over plywood and recycled rubber underlayment addition, R-86 (rater indicates R-120 for both) new 10” rafters, the resulting cavity filled with closed cell foam, and then four inches of Styrofoam over plywood and recycled rubber underlayment

Windows and Doors

  • Marvin Integrity windows on the north, east and west sides of the building with Comfortex, Comfor-Track Plus cellular shades; on the south side Magnetic One Lite storm windows by Allied Windows interior of the rebuilt antique original windows and exterior wooden storm sashes.  The Marvin casement windows have a U value of .29 and SHGC of.30. The new doors are made by Thermo-Tru and are Energy star rated with a U value of 0.26 and a SHGC of 0.17

Mechanicals

  • Climate Master Tranquility TT038 Ground Source Heat Pump      (Energy Star Rated) (6894 Heating degree days per designer)
  • LifeBreath (200Max) Heat Recovery Ventilator (Energy Star Rated)
  • Ultra-air Whole House Dehumidifier 100V(Energy Star Rated)
  • Air King ESSEV 30 kitchen range hood(Energy Star Rated)
  • (6) ceiling fans(Energy Star Rated)

Lighting

  • 19 Energy Star rated either CFL or LED light fixtures with the remaining 14 CFL equipped recessed fixtures

Renewable Energy

  • Photovoltaic – (40) 210 watt Evergreen panels on (5) pole mounted racks, 7000 SMA Sunny Boy Inverter (Engineer specified a 7.4 kW system to run house and charge future electric car.  The PV contractor suggested 40, 200 watt panels to equally balance arrays across 5 poles but substituted 210 W panels at the time of installation which resulted in a 8.4 kW system.)
  • Solar Hot Water – Velux Model CLI-U12SKOW/L218EL, SRCC Rated SEF 3.6, 80 gallon Solar Hot water system with electric timer, interconnected with GSHP well to prevent overheating.

Appliances

  • Samsung Induction Range
  •  Samsung Energy Star (ES) dishwasher (DMT300)
  •  LG Energy Star refrigerator (LFC20760)
  • LG Energy Star clothes washer (WM2016C)
  •  Simplicity Central Vacuum System
  • Car charging station – Leviton Evr-Green 160
  • Home electric use monitoring system – The Energy Detective (TED 5000)
  • Exterior Manual Solar Clothes Dryer

Insulation

  • HeatLok Soy closed cell foam insulation by Demilec

Plumbing Fixtures

  • All Water Sense fixtures. Water usage is approximately 33 gals per day per person.

Roof Construction

  • Sprayed foam underside of new or existing deck and 4” of Styrofoam over Strong Seal Rubber underlayment. Finished with furring strips and standing seam metal roofing

Wall Construction

  • 8” double offset stud wall new addition and all existing exterior walls to offset thermal bridging and increase depth of foam insulation

Wall Finish

  • American Clay over existing plaster or new wall board throughout

To see the Coon’s poster board presentation please click here!

The Cave Family Residence
Northampton, MA

Architect: Coldham and Hartman Architects, Amherst, MA
Builder: Wright Builders, Inc., Northampton, MA

What Kyle and Carolyn had to say about their home…

“Inspired by issues of global warming, our goal for our new home was to create a comfortable, modern living space that produced more energy than it consumed.  We also hoped to produce enough energy to power an electric car to provide the majority of our transportation.  And we hoped to do this in a home that would be inviting and that could be built with “green” materials and ambitious, but proven, building techniques.

Of course, we also had aesthetic and other design goals, including aging in place, living exclusively on one floor, if necessary. As the design goals came into focus, we found that design decisions taken for other reasons kept expanding our south-facing roof.  So, although great thought and care went into lowering the energy demands of the house, we also saw an opportunity to install a large, grid-tied PV array that would allow us to provide renewable energy back to the grid and reduce carbon emissions beyond what our own house would be saving. Our goal was not to achieve net-zero by brute force, but to provide as much environmental benefit from our roof as possible.

Purchasing an electric car almost as soon as we moved into our house was also a goal. Our Wheego (the only electric car brand commercially available in our area in 2011) has been our primary source of local transportation since July of 2011.  We have driven it over

8000 miles in that time (usually car-pooling to work or errands) and our PV array has provided sufficient power for the house and car with plenty to spare to share with our neighbors and to contribute significant electricity credit to charitable organizations.”

Building Description

This home is located on a nearly-stranded flag lot at the end of a cul-de-sac in Hadley, MA and oriented with the long axis facing Solar South.

Net Zero Energy design was achieved by deliberate creation of very low load building (23kBtu/h, ~8Btu/sf/hr peak load), high efficiency all-electric systems, and a PV system which grew to overtake the entire southern roof.

Windows were tuned by orientation to maximize solar gain. Window wells at the basement level provide plentiful light to the lower level. High-R assemblies and very low infiltration rates were achieved to minimize heat loss and maximize internal comfort and durability.

Occupancy

This home is occupied by two people full time.

During vacations (one week in December, 17 days in June) the home was occupied by only one person. For five days in August, they left the building unattended.

Days of Occupancy: 3 6 0

Person Days of Occupancy: 6 9 6

Cost of Building Construction

Building Cost: $809,582, not including site work, design costs, porch or garage. Includes PV cost AFTER the 30% Federal Tax Credit.

Square Footage of Building, including partly conditioned basement space: 3,644 sf

Cost per SF: $22 3 /s f

Envelope

Assembly Insulation Type Thickness Assembly R-value
Sub-slab Continuous RigidFoam (Type IX EPS) 4” R-20
Foundation Wall- Superior Wall Continuous RigidFoam EPS 2.5” R-10 for R-28 Whole wall
Foundation Wall- Interior Cavity Formaldehyde-freeFiberglass Batts 5.5” R-18 for R-28 Whole wall
Above Grade Wall Dense-packCellulose 11.5” R-40
Flat Attic Dense-packCellulose 16” R-57
Cathedral Ceiling Dense-packCellulose 16” R-57

 

Tested Air-tightness: 580cfm50 = 0.89ACH50 = 0.08 cfm50/sf of shell.

Windows

Units – Casement, Awning, Fixed Whole-window U-value SHGC
South 0.19 .61 Glazing (0.42 whole unit)
North, East, West 0.17 .37 Glazing (0.25 Whole unit)

 

Mechanicals

Type Make / Model Comments
Space Heating Mitsubishi City-Multi S- Series 4-ton capacity, 4 zones. One zone (basement area) not in use (no heating required, and used only occasionally as guest quarters)
Space Cooling As above
Hot Water Steibel Eltron Heat PumpHot Water Heater Accelera300 COP near 2.5 expected
Ventilation Venmar EKO 1.5 HRV 82% Sensible effectiveness
Electric Car Wheego Consumed 2630kwh in 13 month period.

 

Lighting

CFL, Strip fluorescent, and LED lighting installed throughout, with 5 halogen fixtures. All lighting and appliances meet Energy Star Tier III requirements for Massachusetts.

Renewables ( P V )

Total Capacity (DC):  21.6kW

Modules: (103) “Suntech 210” panels

Inverters: (4) Inverters. 3 by Aurora, 1 by Fronius.

Projected output of PV: 23,455 kWh / year

Actual output for year in question: 29,944 kWh

To see the Cave’s poster board presentation please click here.

 

The Putney School Field House

Putney, VT

Architect: Maclay Architects, Waitsfield, VT

“This is not just a gym…We want this to be a place where our students can learn about being environmentally responsible, so that later in life, when they are making choices, they can say, ‘It’s possible. Our gym at school did it this way’.” – Randy Smith, Putney School

“The design process for the Putney School Field House started from the client’s request, to design the highest quality environmental building within their budget. The team modeled and evaluated a range of energy and environmental building alternatives, comparing construction costs, 30-year operating costs and CO2 emission.

Some options were removed from consideration almost immediately because they did not go far enough in reaching the School’s sustainability goals. The net-zero option gained final approval from the school. From the School’s perspective it seemed much easier to raise the extra money needed for the construction of a model building than for an endowment for ongoing operating costs for a less-efficient building. The School also decided to seek platinum LEED certification for the project to confirm their efforts with third-party verification.

Throughout the design process, Maclay Architects, working with the design team, conducted multiple day-long work sessions with students, faculty and staff, focusing on key design points. While these sessions added time, voices and viewpoints to the design process, they allowed for a building that speaks of and to the school community. Upon completion, educational signage was placed throughout the building to explain the unique building features and enhance the experience of visitors through learning.

Super-insulation and extensive air sealing were integral to reducing the energy consumption of the facility. To reduce heating energy use by 77% compared to the ASHRAE Standard 90.1-2007 baseline building (Appendix G), the following high insulative levels were used: R-60 roof, R-45 walls above grade, R-20 slabs, R-20 foundation walls below grade and R-5 windows. Through careful design and execution the building achieved a tested air leakage rate of 0.065 cfm/sq ft. of above ground building shell at 50 pascals test pressure or 1,625cfm-50 total air leakage rate. 

Consideration of mechanical systems included both ground-source and air-source heat pumps. Though the air-source system was less efficient than the ground-source system, the solar panels required to cover this inefficiency required less investment than the difference of cost the systems. Based on the cost and the simplicity of the system, the school chose to install the air-source system. To achieve the zero energy goal an investment in renewable on site renewable energy systems included 36.8 kW of solar tracking collectors installed to the north of the Field House.

Construction on the Putney School Field House began in 2007 and was completed in October 2009. The 16,800 square foot Field House is New England’s first net-zero athletic building and received LEED Platinum certification from the U.S. Green Building Council.”

OCCUPANCY STATEMENT:

The Putney School Field House is utilized as a training and workout gym by all students and faculty.  The school hosts indoor sporting events such as basketball games in the Field House, and it functions as an informal gathering space for students and a more formal gathering space for campus events.

Most students, faculty and staff live at the school and when school is not in session many other groups and individuals utilize the campus space, the Field House is utilized 365 days a year. Though, there are only three offices providing space for full-time occupants, when you factor in the larger groups that utilize this space for shorter periods of time, the Field House averages 78 people per day, resulting in 28,470 person days of occupancy.

COST OF CONSTRUCTION:

The Putney School Field House was completed for $5,106,000

The total conditioned square footage is 16,814 SF

The square footage cost is $304/SF

MAJOR ENERGY RELATED SYSTEMS:

Building Envelope
Sub Slab – 4” EPS under whole slab: R-20
Slab Edge – 3” EPS at slab joint: R-15
Foundation Wall – (no basement) 2” EPS panel to 48” depth: R-10
Above Grade Wall – gym wall: 17” of cellulose insulation, all other spaces: 8” of cellulose and 2” of Poly-isocyanurate: R-45 (average between the two systems)
Flat Attic – (all roof)9” continuous Poly-isocyanurate: R-60
White TPO, Energy star roofing used on all roof surfaces
Cathedral Ceiling – no instances
Air Infiltration – measured at 1,625 cfm at 50 pascals, 0.065 cfm50/SF exterior surface area

 Doors/Windows (U-value and SHGC):

Triple-glazed, low-e, argon filled: U-value – 0.15, SHGC – 0.28, VT – 0.49
Skylights in wellness spaces and offices (Velux), double-glazed, low-e, argon filled: U-value – 0.4, SHGC – 0.34, VT – 0.54
Skylights in gymnasium (Sun Optics), triple-glazed, prismatic acrylic: U-value – 0.35, SHGC – 0.74, VT – 0.66
Exterior Doors: heavy duty metal with insulated polyurethane core – 20 psi, 1.8 pcf, ½” max void in all directions

Mechanical Systems

Space heating – Daikin Multi-City VRV air source heat pumps, 2.3 estimated annual heating COP, 7.8 estimated annual heating HSPF based on modeling
Outdoor units: ground units: RXYQ192PTJU and RXYQ168PTJU
Heating delivery by Daikin wall mounted units: FXAQ07MVJU, FXAQ09MVJU, FXAQ12MVJU, FXAQ18MVJU, FXAQ24MVJ
ERV – SEMCO enthalpy wheel, 75% effective, average

Natural cooling – gym utilizes automatically operated high and low windows for cooling
Lavatory water heater, 0.75 GPM instantaneous, 100°F, EX65TFS-100°
Heat pump water heater, E-Tech R060
80 gal electric water heater, Hubbell E-80-4.5-4.5-SL
Manual boost provided in exercise rooms
Locker rooms and baths ventilated when occupied, via occupancy sensorSpace cooling – Daikin heat pump can supply cooling, heat pump is disabled for cooling, except if a zone requires simultaneous heating.  This is only enabled for internal office
Hot water – electric hot water systems
Ventilation – Dedicated ventilation, constant volume in small spaces, variable volume in gym (CO2 and RH control)

Renewable Energy

16 Zomeworks tracking arrays, Modules 160 SunPower, SPR-230-WHT
36.8 kW peak power
46,000 kWh/yr expected average system output
11/17/2011 – 11/15/2012: 54,405 kWh produced

Lighting

High efficiency, Super T8
Automatic step-dimming in gym
Daylight cutoff in other spaces
Occupancy sensors in all occupied spaces

To see the Putney Field House presentation board presentation please click here.

Nakuset Way
Princeton, MA

Engineer: R. Carter Scott, Transformations, Inc., Townsend, MA

What engineer, Carter Scott, has to say about the home…

The clients came to visit the Transformations Coppersmith Way Development in Townsend on the National Solar Tour in October several years ago.  They were interested in building an energy efficient historic looking home.  They had built their existing home some 20 years previously and wanted to upgrade to today’s standards.

With the husbands engineering background, he was very interested in the details that were evolving on how to super-insulate a home and then power it with renewable energy.  Several times he visited the Coppersmith Way project to see what was the latest and greatest. 

Kraus Fitch architects worked with the Clients to create a beautiful layout that included a first floor master, two additional bedrooms, an open floor plan with vaulted ceilings and a sun room towards the rear.  The owners incorporated a “barrel roll” in clapboards on the front of the home.  We used Hardy Plank siding on the other three sides.  The first floor windows had 12 over 12 panes of glass.  The front door had bulls eye glass over it.  A large chimney facade stands proudly in the center of the main roofline.

With the front of the saltbox facing north, we were able to get 14.4 kW of SunPower panels on the rear roof facing south.  This helped our Energy Star rating to come in at a -9.  The home is an all electric home.  During 12 months of living the utility bills show only 5,331 kW hours of electricity were consumed.  During the same time the solar electric system generated 15,867 kW hours of electricity, or 10,536 more kW hours than it consumed.  At a conversion rate of .33 kW per mile, this allows for 31,900 miles of electric driving.  With a zero energy home, we can reduce our share of 48% of the carbon associated with the building sector.  With energy positive homes like this we can also reduce our share of the 33% of carbon associated with the transportation sector!

The home has a heat recovery ventilation system and three mini-splits (two on the first floor and one on the second floor) which supply quiet heating and cooling to the home.  An air source heat pump water heater in the basement supplies ample hot water for the home.

 The walls are 12″ double studded 2×4′s with a 5″ gap between the two walls.  A 1.5 inch layer of foil faced rigid was added to the outside.  On the inside layer of the sheathing we sprayed a 3″ layer of closed cell foam.  The remaining wall was filled with low density foam.  The cavity insulation value of this assembly was R-60.  The R-20 basement walls have 3.5″ of closed cell foam and a fire protection coat of paint.  The slab has 2″ of rigid for a R-Value of 10.  The R-5 windows are triple glazed and filled with krypton gas.

 The home received an Energy Star Tier 3 certification in Massachusetts and construction was completed in the fall of 2011.”

Days of occupancy. 

The home was occupied for the 12 month period.

Person days of occupancy

There are 2 members in the household.

Cost of building construction, excluding design fees, site preparation, and unconditioned space was $360,465.  The square footage of the conditioned space, measured from the exterior is 3,927 square feet.  This includes the conditioned basement but not the garage.  The cost per square foot, including the PV system was $91.79.

Building envelope: For each applicable item below, please list insulation material used and thickness/assembly R-value.

Subslab:  2″ rigid, R-10
Slab edge:  2″ rigid, R-10
Foundation wall:  3.5″ closed cell foam, R-20
Above-grade wall:  12″ double stud walls with 9″ open cell foam (R-33) and 3″ closed cell foam (R-18); 1.5″ foil faced poly-iso on the exterior of the sheathing with strapping (R-9).  The total cavity insulation of the walls is R-60.
Flat attic:  18″ cellulose, R-67
Cathedral ceiling:  2″ closed cell foam, R-12, followed by 14 inches of R53 blown in cellulose.  Total cavity of R-65.

Doors/windows:

List window U-value and SHGC:  Windows U-value of 0.20, SHGC of 0.23.

Mechanicals:

Space heating:  3 Mitsubishi mini splits, MSZ-FE12NA indoor units, MUZ-FE12NA outdoor units, HSPF energy efficiency rating of 10.6
Space cooling:  Same 3 Mitsubishi mini splits, MSZ-FE12NA indoor units, MUZ-FE12NA outdoor units, SEER energy efficiency rating of 23
Hot water:  Steibel Eltron air source water heater
Ventilation:  Fantech HRV model 1504.

Lighting

Compact florescent.

Renewable energy

Make/model/number of major components (e.g. PV panels, inverter, solar hot water panels, tank, other renewable features):  64 SunPower PV panels, 225 watts each with individual Enphase micro-inverters.
Peak power of the PV array (kW) or other renewable feature:  14.4 kW
Projected annual production of the PV array (kWh) or other renewable features: ~15,000 kilowatts per year.
If known, the actual annual production of the PV array (kWh) or other renewable features:  The actual annual production was 15,867.

 

 

 

 


 


 

 

2013 – Runners Up

More models of efficiency

Any building that meets the rigorous criteria to even be considered for NESEA’s annual Zero Net Energy Building Award deserves a shout-out. These runners-up, too, are showing us the way to a sustainable built environment. They have won our admiration, if not our prize.

The Urasche Family Residence

Maynard, MA

Here’s what Andrei Urasche had to say about his home…

Our home is a newly constructed single-family residence located in downtown Maynard, Massachusetts. Maynard is a micro urban community west of Boston full of sidewalks, stores, and eateries.  We reside in the house with our two children.

As potential first-time homebuyers we had initially searched Maynard for an existing starter home that would provide 1) comfort 2) healthy indoor air quality 3) walkability enabling us to function as a one-car family and 4) outdoor space for our children to play.  But what we found left us uninspired. We envisioned living in a passive solar home that was efficient, sunny, and contemporary and wondered: is it possible for a family on a small budget to build such a home onsite using conventional methods and materials?

Initially we had doubts, and almost abandoned the idea. But visiting the three winning entries of the Massachusetts 2009 Zero Energy Challenge encouraged us. We committed to the project when we found a rare 1/4 acre lot in Maynard perfect for our needs.  To stay within budget we kept the footprint small at 1248 sq ft and the house was designed with multi-functional spaces on a single floor. The result of the integrated design team approach is a solar energy home that is beautiful and comfortable and which reflects our values and our aesthetics, while more traditional choices for exterior materials and details allow the house to fit into our New England neighborhood. And with ample attic storage and no need for a furnace we gratefully omitted the New England basement. The design also reflects the idea that ‘home’ is the outdoors, too.  We included three exterior doors for easy access to the patio, yard and garden. The great room with its vaulted ceiling is filled with natural sunlight such that we rarely need electric lighting before sundown.

The passive solar space heating, solar hot water system, and the superinsulated envelope result in very low energy use, while the solar PV array produces more energy than what is used on site. What makes our house unique is that we are net-zero energy not just on a year-to-year basis, but every month since the PV and solar hot water systems went online we have produced as much or more than we consumed—even in the coldest and cloudiest months and without sacrifice to comfort or convenience.  Our 4,000 kWh yearly surplus would cover the energy needed for daily driving with the electric car we hope to someday acquire. Other sustainable features include Energy Star appliances, WaterSense fixtures, and a rain water collection system for gardening.

One unexpected result from building in a downtown location is the community response.  From passers-by and groups of students to NESEA open house participants, our community wants to learn from what we have done.  Our message is simple: sustainable, comfortable, and attractive net-zero homes are now within reach of moderate income families. We will continue to send this message as we enjoy our home for years to come.”

Occupancy statement

The house is used as the only residence for our family of four, which includes two children. One grandparent has lived with us for the entire duration of a two-month visit. During the last 12 months we had 5 days of vacation with the entire family away from home.

Days of occupancy: 360

Person days of occupancy: 1500 (360 x 4 + 60)

Cost of building construction

Total conditioned area: 1248 sq.ft.

Building construction: $243,000. This is the project total with the general contractor, and it includes site-work, such as excavation for foundation and utility connections, fees for connection to utilities ($5000 for town water and sewer), landscaping ($5,000), solar PV system ($36,900), solar hot water system ($8,000). The rebates and incentives are not accounted for in this total cost.

The five major energy-related systems

The house has received Energy Star certification (Tier III), with a overall HERS rating of -8.

Building envelope

All XPS rigid insulation boards are Zero Ozone Depletion Potential XPS, 25 psi, EnergyStar, Dow.

Subslab: 6” total thickness rigid XPS (3 layers of 2” thick boards), entire area, R-30

Slab edge: overall R30, but complex detail as depicted on the presentation board.

4” total thickness rigid XPS (3 layers of 2” thick boards), R-20.

6” thick section of concrete foundation wall above grade

2” thick rigid XPS exterior insulation with protective coating (Tuff II Coating, Styro Industries), R-10

Foundation wall: 2” thick rigid XPS exterior insulation (R-10) below and above grade, entire depth of foundation wall to the top of foundation footing (4 ft). No basement.

Above-grade wall:

Double stud wall, 12” wall cavity, dense pack cellulose (GreenFiber Cocoon2), R-43

Cedar board siding (1”) with vented rain-screen (3/8”).

Flat attic: 24” depth loose fill cellulose (GreenFiber Cocoon2), R-80. Cold attic (vented).

Cathedral ceiling: 24” depth loose fill cellulose(GreenFiber Cocoon2), R-80. Cold attic (vented).

Doors/windows:

Windows: Because window configuration is optimized for passive solar space heating, they have different solar heat gain coefficient (SHGC) and U-values, based on their orientation: high SHGC on the South side, low SHGC on all other sides. Of the total 155.6 sf glazing area, 66% is on the South side, 9% on the North side, and 25% on the East and West sides.

All windows are Inline Fiberglass, Series 325, triple-pane argon filled. Listed SHGC and U-values are full frame. See the table below for the detailed list:

Window name

Orientation

Area (sq.ft.)

U-value

SHGC

Great Room, center top

S

16.00

0.19

0.53

Great Room, center bottom

S

8.00

0.21

0.41

Great Room, sides

S

34.00

0.19

0.53

Master Bedroom, fixed

S

11.33

0.18

0.47

Master Bedroom, operable

S

11.33

0.22

0.41

Flex Bedroom, fixed

S

11.33

0.18

0.47

Flex Bedroom, operable

S

11.33

0.22

0.41

Master Bedroom W

W

13.69

0.20

0.25

Bedroom 2

W

13.69

0.20

0.25

Dining

N

8.03

0.20

0.25

Kitchen

N

5.50

0.20

0.25

Flex Bedroom E, fixed

E

11.33

0.16

0.28

 

Doors: Listed U-values are full frame.

Door name

Area (sq.ft.)

U-value

Main East, with 1/4 Lite, 1″ IG Argon filled, Low E

20.00

0.19

South, solid

17.78

0.14

North, solid

17.78

0.14

Access to attic storage:

West: EZ Hatch Attic Access Scuttle Door, dimensions 22″ x 30″, R-42

East: Fakro Insulated Wood Attic Ladder (22″x 47″), R-5.2 + R- 40 rigid board cap

Mechanicals

Space heating:

Main space heating: passive solar as described in the “Renewable Energy” section.

Electric backup: Mitsubishi Mr. Slim MSZ-FE12NA / MUZ-FE12NA (H2i) air source split-system heat pump. It truly operates as a backup heating source: after sunny days it’s needed only late at night and intermittently during cloudy days.

Space cooling:

Mitsubishi Mr. Slim MSZ-FE12NA / MUZ-FE12NA (H2i) air source split-system heat pump. Used for seasonal air dehumidification and cooling.

Roof overhangs (2 ft. deep at a ground-level height of 8 ft.) are used to limit direct solar heat gain during cooling season, and the large concrete slab thermal mass provides buffering to temperature variations.

Hot water:

Solar domestic hot water as described in the “Renewable Energy” section.

Ventilation:

Fresh air ventilation system meets ASHRAE 62.2-2010 specifications.

Balanced continuous whole-house heat recovery ventilation, Venmar EKO 1.5 HRV (EnergyStar), ductwork in condition space.

Bathrooms and utility/laundry room spot ventilation provided by HRV system in higher airflow mode.

Kitchen spot ventilation provided by range hood (Broan QDE30, EnergyStar) exhausted to outdoors through baffled horizontal duct.

Lighting

The house has been designed for optimum natural lighting. Light fixtures have compact fluorescent (CFL) and LED lamps. 

Renewable energy

The house integrates three solar energy systems: passive solar space heating, solar domestic hot water, and a solar photovoltaic system.

Passive solar space heating: direct solar heat gain through high SHGC south-facing windows, with the finished 4.5” thick concrete floor providing the thermal mass for thermal collection and storage. Concrete slab is passive with no additional radiant heat source, and to assure thermal comfort for occupants it has been designed as a thermal island, with R-30 under slab and R-30 overall slab edge insulation and additional below grade R-10 exterior foundation wall insulation.

Solar domestic hot water: Two SunEarth EC-32 (4′x8′) flat panel collectors, (SunEarth rebranded) Rheem Solaraide HE 80G tank with heat exchanger and electric element backup (240V, 4500 W).

Solar PV system:

Solar PV Size: 6.15 kW (STC)Residential roof mountOrientation: True SouthTilt: 37 deg.Photovoltaic cells: ribbon siliconSolar PV Array: 30 Evergreen Solar ES-A-205-fa3

Array configuration: 2 strings of 15 panels each

DC/AC Inverter: Solectria PVI5300, 240 V AC

Utility grid interconnect, distributed generation unit, net metering.

 

Projected annual production: 8,053 kWh

Annual production (Dec. 2011 – Dec. 2012): 8,292 kWh

Online monitoring: http://www.ursache.com/solar-energy-house/

To see Andrei Urasche’s poster board presentation please click here.

 

Brian Butler & Boston Green Building

Medford, MA

About Brian Butler’s home…

“Brian Butler and his company Boston Green Building recently retrofitted and remodeled his home in Medford, MA (a continental climate). The house was undertaken as part of a pilot program administered by the regions electric and gas company National Grid. To demonstrate the feasibility of reducing energy use in existing structures by 50% or more, the untility provided partial funding for this and several other deep-energy retrofit projects in Rhode Island and Massachusetts.

 The house is a two-family Dutch colonial built in 1908. It has two apartments totaling 3,200 square feet. Though previous owners had replaced the siding, its thermal performance was dismal. The wall cavities weren’t insulated, as were most of the third-floor ceiling cavities. The gambrel rafters had some loose batts, and there was spotty cellulose in the attic ceiling. Space heating was provided by an overworked pair of natural-gas boilers and distributed by steam radiators, with domestic hot water from 50-percent-efficient standing-pilot tank-type heaters. Blower-door tests showed that both units leaked around 3,500 cfm.

Brian’s plan for the renovation aimed to insulate the exiting framing cavities, wrap the entire structure in rigid foam, replace windows, and upgrade mechanical systems including the addition of a solar PV array. Brian moved into the upper level while work commenced meaning the second unit wouldn’t get the interior insulation or air-sealed drywall. While this would result in a slightly lower insulation values the project opened up a new market of retrofitting condos and apartment style housing alike.

Post-project blower-door tests showed air infiltration reduction from 3,500 cfm to just 350 cfm in the lower unit while the upper, untouched on the interior, reduced to 1,800cfm. With the combined effects of this projects deep energy retrofit and leased PV solar array energy costs have plomited. The house represents an 82% reduced annual energy consumption from its baseline of 37,389 kwh to just 6,819 kwh. Given the houses overall performance in combination with the PV solar array the house’s energy consumption is reduced 97% to a mere 846 kwh annually – an average of 70.5 kwh a month. Brian has retrofitted a building to generated energy while conserving it. This brings attention to the untouched methodologies of home renovation.”

Energy – Related Systems

Much of this information can be connected to Brian’s article published in JLC included with additional documents.

Building Envelope – Featured on DIY’s This New House

  • Dense-pack cellulose was blown into existing 2×4 stud wall cavities
  • 7/8” existing board sheathing wrapped with HardieWrap weather barrier –  carefully lapped and taped. – another stud wall, 2×3, was constructed behind the existing to create another layer of blown packed celluslose.
  • Rough Openings also lined with HardieWrap.
  • 2 layers of 2” foil faced polyiso board and a single layer of 1” layed onto the exterior – all seams staggered and sealed with Dow Weathermate Tape. A minimal amount of screws were used for the first two layers.
  • 1×3 strapping screwed with 8” roofing screws was used to provide ventilated nailing base for fiber-cement siding and means of better securing foam.
  • Outer layer of foil face serves as a drainage plane and primary air barrier; the house wrap acts as a secondary air barrier.
  • The overall insulated wall would extend to 16” in depth tightly sealed with R – values reaching R-54
  • Instead of cutting off the rafter tails as it would weakened the roof structure – house wrap was cut and fitted around rafter tails. Edges were then sealed with spray foam. 10” of closed cell foam was then sprayed into the roofs rafters completely burying them. This created a continuous seal with the edges of the house wrap.
  • The attic floor received a flash coat of foam for air-sealing followed by a 20” layer of loose-fill cellulose.
  • The existing chimney was removed leaving a convenient chase for running water lines, HRV ducts, and electrical conduit to a utility room in the basement.
  • The basement was too low for living space – The thermal envelope was decided to wrap at the first-floor joists.
  • The frame of the house was balloon-framed leaving studs toenailed to the 4×6 sill – spray closed-cell foam was installed against the exterior sheathing around the sill filling the space where the studs and joist ends meet.
  • 1” foil-faced polyiso was attached to the bottoms of the joists. Dense packed cellulose was then added along wit a second layer of rigid foam followed by strapping.

Doors/Windows 

  • The buildings orientation and shade from neighboring houses meant for limited passive heat gain through windows.
  • Themotech casements on the south side of the building made the best of this condition offering a solar heat-gain coefficient of .61 and low U-factor of .19. (Most of the windows were supplied by EcoShield from upstate NY)
  • Tilt-turn windows from German Manufacturer Schuco offering tripled pained glass and R-values of R-6.

Mechanicals

  • Three-head ductless minisplit from Mitsubishi provides heat from the downstairs until; the upper apartment is heated with an AO smith water heater piped to a Unico fan-coil system. Each unit is also equipped with its own 90-perfect-efficient Zehnder HRV. A grid connected 7kw photovoltaic array supplies the lower unit with electricity.

 To see Brian Butler’s poster board presentation please click here.

The Miller Family Residence

Newton, MA

Architect: Maclay Architects, Waitsfield, VT

See what Maclay Architects had to say about the home…

“This new residence in the Boston suburb of Newton, MA, achieves net-zero within a neighborhood context. In the owner David Miller’s words, “climate change is the issue of the century,” and this house is built to address that fact. He and his family also take small steps each day to reduce their energy consumption, like using the clothes dryer as little as possible and keeping the thermostats low, Karen Miller notes, “The savings we are getting is because of how our home is built.”

The Millers chose the site for their home because of the location. The close proximity to the T allows them to use public transportation regularly, an adjacent park provides recreation out the front door, and the small center within walking distance has restaurants and shops. A small existing home on the property was deconstructed and building materials salvaged for reuse to the greatest extent possible.

The house is designed with the main entry facing the main street, preserving the formal and traditional street presence typical of the neighborhood. However, a large wing of the home is built at a 45 degree angle to the street, maximizing the south facing roof.  This roof is covered in photovoltaic panels. Solar domestic hot water panels are located on the south-east facing slope of the front gable. Large south facing windows optimize passive solar gain to help heat the house and provide a connection to the outdoors for the occupants.

The house is super-insulated, with an R-20 basement, R-40 walls, R-5 windows and an R-60 roof. Heating and cooling, if needed, is provided by an air-source heat pump, which is powered by the electric provided by the home’s PV panels.

The Miller’s new home uses 88% less energy than the couple’s previous home, built in 2005. Additionally, the production of energy on-site will save the couple approximately $6,000 annually in energy costs. Combining energy rebates with the reduced energy costs, the renewable energy system is on track to pay for itself after only four years.

The Miller’s recognize their net-zero home is large, compared to the US average home size in 2010 of 2,169 SF. However, for the neighborhood, their home is on the small end. A quick search of public property records for homes built in the neighborhood in the last 10 years, gives an average size of 4,553 SF of above ground living area, putting the Miller’s home in the 29th percentile for size. An important factor for the Millers when designing their home was to create a space where they could raise their two children, but also where they could work. Both of the Millers work out of their new home, decreasing their overall energy footprint, but increasing both the size requirement for the house and its overall energy demand.

OCCUPANCY STATEMENT 

The Newton home is a full-time residence and office space for its occupants. The four person family (2 parents and 2 children) live here year-round and are only away from the home about 4 weeks a year for family vacations. Throughout the year, the family welcomes numerous family guests into their home and last year hosted multiple public and fundraising events for dozens of people, including food preparation. Taking these factors into account the occupancy statements for the Newton home are as follows:

≈ 340 Days of Occupancy

≈ 1460 Person Days of Occupancy

COST OF CONSTRUCTION

Square footage of conditioned space – 5,329 SF

The owners have declined to release the construction cost for their home.

MAJOR ENERGY RELATED SYSTEMS

  1. Building Envelope
    • Sub Slab – R-20, 4” XPS rigid insulation
    • Slab Perimeter – R-20, 4” XPS rigid insulation
    • Foundation Wall – R-32, 2” XPS, 6” loose fill cellulose
    • Above Grade Wall – R-40, 2” poly-isocyanurate, dense pack cellulose in 2×8 wall cavity
    • Roof – R-67, 18” loose fill cellulose
    • Air Infiltration – measured at 1,111 cfm at 50 pascals,
  1. Doors/Windows (U-value and SHGC):
    • Windows – low-e, tri-pane, argon filled, 0.20 U-value, 0.24 SHGC, 0.39 VLT
  1. Mechanicals Systems
    • Space heating – (2) Mitsubishi Air Source Heat Pumps
    • Outdoor ground units: PUMY-P48NHMU
    • Heat delivery by Mitsubishi wall mounted units: PEFY-P36NMAU-E, (2)PKFY-PO8NBMU-E, (2)PKFY-PO6NBMU-E
    • Space cooling – to be provided from air source heat pump, if necessary
    • Hot water – 3200 kWh-yr solar thermal, 3 – 4×8 collectors with 120 gallon tank
    • Ventilation – Venmark Eko 1.5 ERV Unit located on 2nd floor
  1. Renewable Energy
    • 42 Sunpower 225 Watt Modules, SPR-225-BLK
    • Peak power – 9.45 kW
    • 12,000 kWh/yr expected average system output
    • 11/16/2011 – 11/15/2012: 13,276 kWh produced
  1. Lighting
    • High-efficiency fluorescent and LED fixtures throughout

To see the Miller Family Residence poster board presentation please click here.

 

Pat Hanson

Brandon, VT

See what Pat has to say about her home…

“It was hard to think of moving from the great energy-efficient solar house I had built nine years earlier in Burlington, VT, but I wanted to be closer to my daughter. Looking for housing in Brandon, I realized that I didn’t want to give up the bright warmth, open design and energy efficiency of my “old” house. The only answer was to build. Everything fell together, as I found a small lot with southern exposure in an established neighborhood, with houses close by on each side, and within walking distance of the center of Brandon. I visited my builder, Chuck Reiss’ new house on the  Green Building Tour and got excited about new developments in the field and the possibility of reaching for net-zero. I immediately began designing, and Chuck agreed to bring his crew down to Brandon. Final plans were drawn up by Dora Coates of Dovecote Designs, with suggestions from my son-in-law, David Martin, who trained as an architect.

Much of the house design is carried over from my previous home. I had known from experience that Chuck’s building techniques (double walls with dense pack cellulose, careful sealing of all penetrations) would give me a tight envelope. The water-to-water geothermal heat pump greatly reduces the energy needed to heat the house and, as a bonus, gives me the comfort of radiant floor heat, as well as freedom from radiators. I keep the heat at a comfortable draft-free 67º. Based on the reduced heat load, solar hot water and energy efficient appliances, Chuck calculated the optimum amount of solar needed to reach net-zero.

The few north-facing windows are triple-glazed, and the large south-facing windows and skylights keep the house toasty warm on the coldest of sunny winter days, while being shaded in the summer by the large overhang of the roof. There is no need for air conditioning. The windows provide splendid natural light, supplemented, when needed, by florescent lighting. Insulating shades, which open from top or bottom, provide flexibility in privacy and shading. The open design, with its upstairs loft and cathedral ceiling, lets the warm air and light circulate through the whole house. All living areas but the study have natural light from windows to the south.

  The 45º angle of the roof not only optimizes the solar collection, but also sheds snow quickly, and it provides excellent high-ceiling storage space, much needed in a house on a slab.

I sacrificed nothing in my move from Burlington (save proximity to Great Harvest Bread). I am glad to have been able to pass another five-star energy efficient house on to a new owner, and I have gained the immense satisfaction of paying no utility or heat bills, except about $30 a year for propane for stove-top cooking (more than made up for by about 1,000 extra Kwh fed to the grid). As Chuck says, I have become a “micro utility” and, he asks, “Why isn’t every house being built this way?””

Occupancy statement:

For the 12-month period before the inverter failure the house was occupied 353 days (12 days of vacation) and 428 person days.

Cost of Construction

Built in 2009-2010, conditioned space cost of  $377,886.00

Incentives and federal credits  $29,167.00

Adjusted Cost  $348,719.00

Sq. Ft Cost  348,719/ 1740 $200.41/ sq. ft

Building Envelope

Subslab 4” extruded polystyrene R-20

Slab edge 2” of foam

House is on a slab, no basement

Above-grade wall 2×4 double wall (9.25”cavity) dense pack cellulose R-34

Flat attic 2×10 and 2×8 (16.5” cavity) dense pack cellulose R-63

Cathedral ceiling (including sloped attic ceiling) 2×12 with horizontal strapping (12.75” cavity) dense pack cellulose R-43

Doors/Windows*:

North-facing: Marvin Windows, 1 clad casement and 2 awning tripane u=.25 SHGC =.25

West-facing: 1 Marvin clad casement double pane u=.35 SHGC =.47

East-facing: 2 Marvin clad double-hung u=.30 SHGC =.30

South-facing: 4 Marvin clad double-hung u=.30  SHGC=.30

10 Marvin clad casement double pane u=.35 SHGC=.47

3 Velux VS sky lights  u=.50 SHGC=/29

Doors: 4 (including attic door) ThermaTru R-7 u=.14

*Only windows on walls within the conditioned space are listed. Over 75% of the                                     surface of these windows faces south.

Mechanicals

Open loop geothermal heat pump feeding radiant heat to both floors, 3-ton heat pump, open-loop to drilled well, GeoStar EWO 30H10SSA

Space cooling not needed

Solar hot water with electric back-up, see below in Renewables

Venmar Constructo 41500 1.p air to air heat recovery unit for ventilation

Lighting

21 hard-wired florescent fixtures, all other lamps and fixtures have compact florescent                   bulbs

Renewable Energy

24 Sanyo HIT210N 210 watt solar roof-mounted PV panels

Solectra PV 15300 inverter

2 Heliodyne roof mounted Golbi 408 solar hot water panels   68 kBTU/ clear day

Superstor Contender Solar tank (SE series, electric back-up),           GFX heat-recovery coil                      for 2nd floor bath

Peak power of PV array 5040 watts

Projected annual production of PV array 6048 KWH

Actual production of PV array 11/22/11 – 11/30/12 was 5,391. This period included an inverter failure from late April to June 15, with 1 ½  months of lost production. No data available for the earlier period.

To see Pat Hanson’s poster board presentation please click here.

Kane Family Residence

Westwood, MA

See what Peter Kane had to say about his home…

The inspiration for this house came from three sources: Marc Rosenbaum (especially the Hanover NH house), Carter Scott (Transformations Inc. and the Coppersmith Way development in Townsend MA) and Sarah Susanka’s book – The Not So Big House. I was introduced to all three by the NESEA Building Energy conferences.

The motivation for this house was the desire to live comfortably in a way that minimized our contribution to global warming. I also wanted to show that not all new homes had to be big, ugly, and inefficient. Lastly, I wanted to employ the Evergreen Solar panels that I had spent the last 14 years helping to manufacture right here in Massachusetts.

 I was very fortunate to work with Carter Scott and Jeff Richards of Transformations Inc. and Rick Gilles of Barnraisers Inc. during the design phase of the project. They did a great job of taking my rough sketches of a one and a half story Maine farmhouse and turning them into a set of construction drawings that incorporated many of the features Carter employed in the Coppersmith Way homes.

I decided to manage the construction phase myself and put in a lot of sweat equity to save money. I was fortunate again to hire Robert Austin of RT Construction to handle the framing and siding. He did a first class job.

Nothing about this house is really new or radical. It uses standard materials and construction practices that are becoming common. It cost about the same to build as a typical home. It’s success lies in the attention to the details – both architectural and energy wise.

Unlike most zero energy homes being built today, this house uses a solar thermal system to satisfy most of its heat and hot water needs. Although it cost more than a pure PV design, the benefits of this system are that it enables the use of radiant floor heating (which is very efficient, comfortable, quiet and draft free), it’s capable of collecting an amazing amount of energy on a sunny day and it enables the use of a simple instantaneous electric water heater for inline backup . The drainback design eliminates the need for antifreeze, eliminates stagnation problems in the summer and is basically maintenance free. Judging by the last years real world results, it worked out very well.

            What I think is great about this house is as follows:

  •  Net positive performance – no electric bills or fuel bills
  •  It’s architecturally pleasing
  • It ‘s the right size – not too big, not too small
  • It’s very pleasant to live in – warm floors, bright      sunlit spaces, cool in the                                                  summer, warm in the winter, quiet, uniform temperature throughout,                                                    comfortable humidity levels in winter
  • Everyone likes the cozy bench seating at the dining table
  • The kitchen layout is great and the pantry keeps it uncluttered
  • The interior windows above the sliding door bring amazing natural light to the                                                         second floor bathroom and master bedroom and allow for natural air                                                        circulation                
  • The vestibule entry with the stained glass window is as practical as it is                                                                     beautiful.
  • The floor grate by the front door is great for preventing dirt from getting tracked                                             inside
  • The wide windowsills are great for plants”


Occupancy:

Except for three weekends, the house was occupied  by at least one person. Since June of 2011 it has been inhabited by me, my wife and my 16 year old son. My college daughter was also home for several weeks. Deducting time for vacations, the total number of person days was 1005.

Cost:

Approximately $150 per square foot ($300,000)

To see Peter Kane’s poster board presentation please click here.

R. Carter Scott’s Adams Circle

Devens, MA

See what Carter Scott had to say about the home…

“In April of 2009, searching for a way to showcase sustainable housing, the Commonwealth’s MassDevelopment put out a Request For Qualifications for developer/builders to design and build single family and multi-family homes at its Devens, Massachusetts residential community.  The purpose of the project was “to provide a replicable example of current and innovative sustainable building practices that are practical for Massachusetts homes.  In keeping with the Governor’s stated goal of moving toward zero net energy development, a goal of the project is to provide a forum for development of zero net energy, or near zero net energy, moderately-priced housing”.

Transformations, Inc. was chosen to build the single family project with a total of 8 homes.  In the summer of 2011 we began construction on the first two homes.  The first home was sold by October.  By the following October in 2012 all of the homes were either sold or under agreement.  We had planned on a 3.5 year build out.  The combination of zero energy homes and the great Harvard public schools seemed to be a potent combination.

The final HERS indexes have ranged from HERS 6 to -37.  The first home has just completed 12 months of occupancy.  The building style is a Greek Revival with the gable end facing the street.  This is the home that is submitted for the ZNEB award for this development this year.  This home represents one of over a 100 zero energy attainable homes in the Transformations development and building pipeline—a sure sign of replicability in the Northeast!

The home starts with a double studded frame wall that is 12 inches thick for a R45.6 cavity insulation level.  The attic has 18″ of cellulose (R-63), the basement walls have 3 1/2 inches of closed cell foam (R-20), the basement slab and slab edge has 2″ of rigid (R-10) and the window are triple pane (R-5).  The super insulated shell allows for a simple Mitsubishi mini split of each of the two floors.  The hot water heater is a 98% efficient Navien unit.  The flat portion of the roof faces towards the South and has a 7.59 kW PV system installed on it.  After accounting for propane use for hot water, the homes net positive energy production for the year was 369 kW. 

The Devens project has been a resounding success on many levels.  These homes met the goals of the MassDevelopment program.  They sponsored two zero energy home workshops to help get the word out to other builders and developers.  Marty Jones, the President and CEO of MassDevelopment, presented a check to the Greek Revival owners for over $500 on December 12, 2012 for the excess energy that they sent into the grid.  The Greek Revival owners were pleased with the aesthetics, comfort and the energy efficiency of their new home.  The Department Of Energy extended the Building America Program for Building Science Corporation to continue our work together.  Transformations was pleased with another model community designed and built to advance energy efficient construction in the Northeast.”

Brief occupancy statement explaining how the building is used, including:

Days of occupancy: number of days anyone is present in the building for the 12-month period during which net zero data is collected).  The home was occupied for the 12 month period.

Person days of occupancy: one person present for one day equals one person day, two people for two days is four person days, and so on.  There are 3 members in the household.

Cost of building construction, excluding design fees, site preparation, and unconditioned space was $188,731.  The square footage of the conditioned space, measured from the exterior is 3,072 square feet.  This includes the conditioned basement but not the garage.  The cost per square foot, including the PV system was $61.44.

The five major energy-related systems. Please list the following:

Building envelope: For each applicable item below, please list insulation material used and thickness/assembly R-value.

  • Subslab:  2″ rigid, R-10
  • Slab edge:  2″ rigid, R-10
  • Foundation wall:  3.5″ closed cell foam, R-20
  • Above-grade wall:  12″ open cell foam, R-45.6 cavity
  • Flat attic:  18″ cellulose, R-67
  • Cathedral ceiling:  none

Doors/windows: List window U-value and SHGC:  Windows U-value of 0.20, SHGC of 0.23.

Mechanicals: For each of the subsystems below, please list component make and model number, plus any comments that might be of interest.

  • Space heating:  Mitsubishi mini split, MSZ-FE12NA indoor unit, MUZ-FE12NA outdoor unit, HSPF energy efficiency rating of 10.6
  • Space cooling:  Mitsubishi mini split, MSZ-FE12NA indoor unit, MUZ-FE12NA outdoor unit, SEER energy efficiency rating of 23
  • Hot water:  Navien 180, 98% efficient
  • Ventilation:  Panasonic Whisper Comfort ERV, model ERV FV-04VE1 in upstairs hallway plus Panasonic exhaust fans in bathrooms.

Lighting:  Compact florescent.

Renewable energy

  • Make/model/number of major components (e.g. PV panels, inverter, solar hot water panels, tank, other renewable features):  33 Canadian Solar PV panels, 230 watts each; Fronius IG Plus 7500 watt UNI inverter.
  • Peak power of the PV array (kW) or other renewable feature:  7.59 kW
  • Projected annual production of the PV array (kWh) or other renewable features: ~8,300 kilowatts per year.
  • If known, the actual annual production of the PV array (kWh) or other renewable features:  Unknown.

R. Carter Scott’s Coppersmith Way

Townsend, MA

See what Carter Scott had to say about the home…

 “The Groton” is an 1835 square foot home Transformations, Inc. built and sold in the Coppersmith Way development in Townsend, MA.  It was started in late 2009 and completed in June of 2010.  This home is a second generation Farmhouse model with a garage under to fit the sloped site.  Many of the energy efficiency features have been honed in on though cost effective evaluations and input from many in the building science field.

The shell and energy efficient features of this home are highly repeatable.  Transformations currently over 100 homes in the development and building pipeline with similar zero-energy specifications.

The cost to get to zero energy has been brought down to $3 per square foot over a stretch code home with a leased PV system.  At these prices, the zero energy homes can spread fast throughout Massachusetts and other states with Solar Renewable Energy Credits.  It is Transformations goal to help speed this process.  The typical home saves about 60% of its energy in the shell, appliances, lighting, hot water, etc.  The other 40% or more is made up though the PV. 

The Groton features a 7.14 kW PV system that is integrated into the surface plane of the roof for a pleasing aesthetic.  We attained the look of BIPV without the cost!  The roof under the PV system was recessed 8” inches to accomplish this.  Black framed mono-crystalline panels further this curb appeal. 

A Navien 180 instantaneous gas fired hot water heater was used in place of any solar thermal systems.  It did not take up any roof space, cost $1,800 to install (as opposed to $8,500 for a solar thermal system) and used only about $43 worth gas over a 12 month period (36 Therms).

The ventilation system used was a Fantech 1504 Heat Recovery Ventilator.  We exhausted the three bathrooms and supplied fresh air to the hallway on the second floor.  This was done at less than half the price of the LifeBreath systems we used previously.

This “Groton” model home was cost effective to build, has excellent curb appeal and is vastly repeatable and scalable. It was built on speculation and sold for $359,900.  The positive energy produced was about 1450 kW hours a year.  This is enough energy to supply a plug in Prius a modest commute, 5 days a week, 50 weeks a year.  With homes like these, we can solve the carbon emissions of the building sector and start to work on the transportation sector as well!”

Brief occupancy statement explaining how the building is used, including:

Days of occupancy: number of days anyone is present in the building for the 12-month period during which net zero data is collected).  The home was occupied for the 12 month period except for 10 days of vacation.

Person days of occupancy: one person present for one day equals one person day, two people for two days is four person days, and so on.  There are 2 members in the household.

Cost of building construction, excluding design fees, site preparation, and unconditioned space was $160,299.  The square footage of the conditioned space, measured from the exterior is 2,699 square feet.  This includes the conditioned basement but not the garage.  The cost per square foot, including the PV system was $59.39.

 The five major energy-related systems. Please list the following:

Building envelope: For each applicable item below, please list insulation material used and thickness/assembly R-value.

  • Subslab:  2″ rigid, R-10
  • Slab edge:  2″ rigid, R-10
  • Foundation wall:  3.5″ closed cell foam, R-20
  • Above-grade wall:  12″ open cell foam, R-46.8 cavity
  • Flat attic:  18″ cellulose, R-67
  • Cathedral ceiling:  none

Doors/windows: List window U-value and SHGC:  Windows U-value of 0.20, SHGC of 0.26.

Mechanicals: For each of the subsystems below, please list component make and model number, plus any comments that might be of interest.

  • Space heating:  2 Mitsubishi mini splits, MSZ-FE12NA indoor units, MUZ-FE12NA outdoor units, HSPF energy efficiency rating of 10.6
  • Space cooling:  2 Mitsubishi mini splits, MSZ-FE12NA indoor units, MUZ-FE12NA outdoor units, SEER energy efficiency rating of 23
  • Hot water:  Navien 180, 98% efficient
  • Ventilation:  Fantech 1504 HRV

Lighting:  Compact florescent.

Renewable energy

  • Make/model/number of major components (e.g. PV panels, inverter, solar hot water panels, tank, other renewable features):  (42) Suntech 170 watt mono-crystalline panels in black frames; (1) Solectria PVI 3000 inverter and (1) Solectria PVI 4000 inverter
  • Peak power of the PV array (kW) or other renewable feature:  7.14 kW
  • Projected annual production of the PV array (kWh) or other renewable features: ~8,000 kilowatts per year.
  • If known, the actual annual production of the PV array (kWh) or other renewable features:  Unknown.

 To see the poster presentation for The Groton please click here.

Sota Construction’s Merriman Way

Pittsburgh, PA

See what Sota Construction Services, Inc. had to say about their home…

Located in the very urban South Side neighborhood of Pittsburgh, 1820 Merriman Way is a part of Riverside Mews, a high density development of 32 units per acre, which is being built on a former brownfield site. All of the townhomes exceed Energy Star requirements. Typically the homes score in the low 50s.  Thanks to a Walk Score™ of 91/100 and a Transit Score™ of 70/100, homeowners at Riverside Mews can enjoy both a sustainable residence and a sustainable lifestyle. 

Extra efforts were taken at 1820 Merriman, and it was marketed as the first net-zero energy home in the city. It is a two-bedroom, 2-1/2 bath townhouse, using 36 photovoltaic solar panels on the roof, geothermal tubing that reaches 450’ into the earth, and a desuperheater that uses excess heat from the heat pump to heat domestic hot water.  Energy consultant MaGrann Associates provided Energy Star certification services which yielded a HERS index rating of -4.

The home was purchased in April of 2011.

Other sustainable efforts include: low-voltage light controls, LED lighting, Energy Star appliances, a white reflective roof, low- and no-VOC paint, bamboo flooring, and exterior siding and decking made partially from recycled aluminum and plastic bags, respectively. The USG drywall contains recycled content, and the concrete block has Allegheny River gravel in it. There’s even a NatureMill undercounter composter in the kitchen that turns scraps into compost in about a week-and-a-half without odor.

Sota Construction Services, the contractor behind 1820 Merriman Way, wanted to emphasize one simple fact in this home: being energy-conscious and living sustainably doesn’t mean you have to sacrifice great design or comfort, but you can enhance it through simple, replicable measures. As Ernie Sota, president of Sota Construction, put it, ‘Green building is not one big thing. It’s a whole bunch of little things, step by step, then putting it all together.’”

Days of Occupancy:

This is a full-time residence occupied by two people. Occasionally, one may go out of town for business for a few days, but the home is otherwise continuously occupied by the other resident.

Person Days of Occupancy:

345 x 2 occupants = 690 person days

Cost of Project:

 

Cost of construction excluding design fees, site prep and unconditioned space: $395,000.00

Sq ft of conditioned space measured from the exterior: 1,930 sq ft.

Building Envelope:

  • Slab Floors: R10 Under, Full U=0.044
  • Slab Edge: R-10.0
  • Above Grade Walls: R-33 UR spray 6-16+5 U=0.035
  • Foundation Walls: CMU, R-13, 4-16 R=14.1
  • Vaulted Ceiling: R60,FG,T-24/II+7 U=0.023

Doors: Therma-Tru, R4.5 U=0.184

Windows: U:0.33, SHGC:0.30 U=0.330

Mechanicals:

  • Space Heating/Cooling: Ground source ClimateMaster heat pump – Htg: 32.1 kBtuh, 4.0 COP. Clg: 26.6 kBtuh, 18.5 EER, with Desuperheater
  • Water Heating: Instant water heater, Gas, 0.82 EF; Heat pump, Elec, 2.50 EF
  • Ventilation: Exhaust Only: 42 cfm, 21.0 watts.

Renewable Energy:

  • Make/Model/Number of major components (e.g. PV panels, inverter, solar hot water panels, tank, other renewable feature, etc).
    • (36) 31/2-by-5 foot Sharp ND-224U1F  photovoltaic array
    • SMA America SB8000US (240V) inverter
    • What is the peak power of the PV array (KW) or other renewable feature?

8 kilowatts

  • What is the projected annual production of the PV array (kWhr) or other renewable feature?  Approximately 8,500 kwh

Lighting: Lighting throughout the home features a majority of LED downlights and a few fluorescent lamps.

To see the poster board presentation for Merriman Way please click here.

 

 

 

2012 – Winner

Ross Family Residence

The winner of NESEA’s annual Zero Net Energy Building Award offers not only energy efficiency, but ideally also comfort, affordability, reliability, and elegance. Congratulations to everyone involved in this project. You are leading the charge on making sustainable energy practices the norm in the built environment.

Location: Amherst, MA
Architect: Coldham & Hartman Architects, Andrew Webster
Construction Management: FCM Smart Build
Construction Services: Holden Builders

Our first deep energy retrofit winner: A home for real people based on real needs

Read what the judges have to say

After intense deliberation, the judges chose to award the 2012 Net Zero Energy Award to the Ross family residence in Amherst, Massachusetts. The panel was deeply divided but ultimately selected this project for several reasons. First, this project was a Deep Energy Retrofit, the first such project to receive the NESEA award. As such, it provides an excellent example of how the construction industry should be upgrading our existing building stock to be more efficient and livable.

The Ross residence also elegantly integrated building systems that addressed the envelope, air-tightness (about 1.0ACH50 for a retrofit), passive heating opportunities, LED lighting and mechanical strategies that reduced the energy requirements to excellent levels. Based on these factors, this project eked its way past a group of other excellent, well-deserving candidates. Because of their attention to a whole-building approach, the Ross family’s PV system was not only able to meet the remaining building load but provided an additional 30% of renewable energy back to the grid.

Although some may argue that this project featured an overabundance of PV, the judges wanted to stress the importance of being a net provider if the owner has the means to do so. Moreover, because the renewable solutions are well-integrated and the home is attractive, it serves as a good example to help promote net zero energy buildings. And although the price tag and size may seem high, the designers dealt quite effectively with what they were given, choosing to save instead of tear down, and doing so for a relatively modest $141/sf.

Maybe most importantly, the design represents a home for real people, based on real needs. As a society, we need to modify the way we live for the sake of the planet. This home serves as an important mode, suggesting an incremental alternative to the way we currently live, and does so with beauty and grace.
It should be mentioned that while not all entries could be awarded first place, all had elements that were truly first-place quality. It speaks well of NESEA that the quality of the entries has increased year after year since the inception of the award.

2012 Runners – Up

Location: Putney, VT
Architect: Maclay Architects

 

Showing students that sustainability is possible—and beautiful—two years in a row

This is not just a gym…We want this to be a place where our students can learn about being environmentally responsible, so that later in life, when they are making choices, they can say, ‘It’s possible. Our gym at school did it this way’.” – Randy Smith, Putney School

The Putney School is a progressive, college preparatory school located in rural southern Vermont. In addition to classroom buildings, the campus includes a working 500-acre farm. The School’s vision for a field house was one that would support a long tradition of excellence in sports programs and serve as a central gathering space for students, while meeting aggressive sustainability goals. The Putney School Field House has the distinction of meeting NESEA’s stringent net zero criteria two years in a row, having also qualified for judging in 2011.
The two-story building features an on-site 36.8-kilowatt solar photovoltaic system, energy-efficient lighting with daylight and occupancy sensors, composting toilets, natural lighting, and earth- and human-friendly materials throughout. The first floor features a gym, a rock climbing wall, ski-waxing room, mechanical room and storage. The second floor, which serves as the central gathering space, includes bleachers that overlook the gym space, offices, locker rooms, and flex space for wellness and strength conditioning activities.
The team assessed five options consistent with the overall vision, including a Base Building Model, a High-Performance model, a Micro-load model, Carbon-neutral building; and a Net-Zero building model. The construction and operating costs for each were carefully studied, with estimates ranging from $3.5 to $5 million. Projected first year energy costs ranged from $22,500 / year to $1,200 / year. Estimated total CO2 emissions ranged from 130,000 LBs/year to 0LBs/year The net-zero option gained final approval, demonstrating how upfront investments in a super-insulated envelope, renewable energy and advanced systems create long-term predictability in future energy costs.

Super-insulation was installed and extensive air sealing was completed on the facility. To reduce heating energy use by 77% compared to the ASHRAE Standard 90.1-2007 baseline building (Appendix G.), the following high insulation levels were used: R-60 roof, R-45 walls above grade, R-20 slabs, R-20 foundation walls below grade and R-5 windows. We achieved a very low tested air leakage rate of 0.065 cfm/sq ft. of building shell at 50 pascals test pressure (0.065 cfm-50/sq.ft. shell) or 1,625cfm-50 total air leakage rate. We attribute the low air leakage to careful envelope design and execution.

Mechanical systems considered for the building included both ground-source and air-source heat pumps. The selected optimal system was an air source heat pump, as cost was the determining factor. To achieve the zero energy goal, investment in renewable energy sources was also required. To maximize performance and obtain long-term value, 36.8 kW of solar tracking collectors were installed to the north of the Field House.

Construction on the Putney School Field House began in 2007 and was completed in October 2010. The 17,500 square foot Field House is New England’s first net-zero athletic building and anticipates LEED Platinum certification from the U.S. Green Building Council.

Click here to see the poster submitted with the Putney School Field House application.

Kraus-Fabel Renovation

Location: Amherst, MA
Owner: Mary Kraus
Architect: Mary Kraus
Engineer: Marc Rosenbaum

What does it take to reach net zero? Not much, and nothing fancy

DESCRIPTION OF PROJECT:
One barrier to broader adoption of ZNE practice is the perception of ZNE as expensive and exotic. In this project we address this issue directly, and demonstrate that ZNE renovation can be straightforward and practicable, providing qualitative improvements, significant savings in energy and carbon emissions, and excellent return on investment. We started with our small, simple, relatively efficient, sun-tempered home, our half of a cohousing duplex built in 1994. What would it take to make it ZNE? Answer: Much less than I had anticipated – and nothing fancy.

Our home was built “Energy Crafted”, with 7” dense-packed cellulose walls and tight construction. Our windows were reasonably good for the time – double-pane, argon-filled, low-e casements. A sealed-combustion propane-fired boiler provided heat and hot water. An exhaust-only ventilation system kept the air fresh. Most of the lighting was CFL. The design was compact and sunny, providing a comfortable living space with three bedrooms in about 1,000 square feet of finished area (1,596 SF conditioned space.) A solar hot water system, installed on our roof in 1999, was shared with our duplex-mates. Before our ZNE renovation, our electricity use averaged 300 kwh/month; yearly propane usage was about 300 gallons. A good starting point, but nothing spectacular.

The first step on our ZNE journey followed one of my favorite sustainable design maxims, “Don’t overlook the mundane”: we bought a new refrigerator, saving an estimated 40 kwh per month. Our path to a ZNE home included:

  • Careful modeling to determine strategies
  • Targeted air sealing (start with a sound envelope!)
  • Reducing plug loads
  • New air-source heat pump to replace propane boiler
  • New HRV to replace exhaust-only ventilation
  • Super-insulated electric water tank as new backup for solar hot water
  • 5.9 kw PV array to cover all energy uses

With PVs now powering all systems – and in spite of a record-breaking winter – our home was net energy producing this past year: 430 kwh net annual production (1.2 kwh/day, 6.5% above load). With all of this in place, our household energy use declined by 23% (using kwh equivalents for the replaced propane).

We love our new heating system. It is a qualitative improvement. One interior point-source unit provides heat for the main floor and upstairs of our cape-shaped home. It is a pleasure to sit beneath while reading on a cold day, and it keeps the whole house a comfortable temperature. A second unit serves the walk-out basement. Although we now officially have “air conditioning”, we have not used it upstairs – a south roof overhang and a deep west porch keep our home comfortable in the summer. We use the basement unit for summer dehumidification, with both qualitative improvement and significant energy savings over previous usage for that purpose.

I view energy-use reduction as an ongoing step-by-step endeavor rather than a one-time project. We plan to continue the process, including switching to LEDs, installing interior storm windows, and chipping away at plug loads. I look forward to seeing how our energy picture continues to improve, and to applying these insights in my architectural practice.

Click here to see the poster submitted with the Kraus-Fabel application.

Eliakim’s Way

Location: West Tisbury, MA
Owners: Matt Coffey and Christine Conley
Designer: South Mountain Company
Engineer: Marc Rosenbaum

Proof positive that there are no net zero buildings . . . rather, there are net zero occupants

PROJECT DESCRIPTION
As part of our quest to bring better and better quality to affordable housing, where the need is greatest, South Mountain Company designed and built a cluster of eight high-performance homes in West Tisbury, Massachusetts in 2010 for the Island Housing Trust.

The houses were designed to enable the occupants to use less energy than their solar systems produce. Half have three bedrooms (1,447 sf) and half have two bedrooms (1,251 sf); all have full basements. The houses are all-electric, each has a 5.04 kW Sunpower solar electric (PV) array, and each received LEED platinum certification.

All major energy end uses are sub-metered and carefully monitored. Our comprehensive data collection led to a detailed analysis called “Zero-Net Possible? Yes!” which has been widely published and cited. After one year, two households – a three bedroom and a two bedroom – achieved zero annual net energy, using less energy than the PV array generated. One of these – house #9 – is our submission, as the other was occupied for only 300 days during the monitoring period.

Two other households were close – within ~1,100 kWh of reaching net zero – and the remainder varied widely. We learned that there are no zero energy houses, only zero energy possible houses which, when combined with zero energy occupants, make zero energy a reality. A distinguishing characteristic of this project is that, unlike most zero-energy buildings which result from the aspirations of the clients, these occupants were chosen by lottery. They weren’t seeking zero-energy housing, they were seeking affordable housing. They got both, and we expect that more of the occupants will become zero energy families as time passes.

Click here to see the poster submitted with the Eliakim’s Way application.

The Groton

Location: Townsend, MA
Designer/Builder: Transformations, Inc.

Net positive at just $3 per square foot above stretch code prices

“The Groton” is an 1835 square foot home Transformations, Inc. built and sold in the Coppersmith Way development in Townsend, MA. It was started in late 2009 and completed in June of 2010. This home is a second generation Farmhouse model with a garage under to fit the sloped site. Many of the energy efficiency features have been honed in on though cost effective evaluations and input from many in the building science field.

The shell and energy efficient features of this home are highly repeatable. Transformations currently has 90 homes in the development and building pipeline with similar zero-energy specifications: 33 homes in Easthampton, MA for Beacon Communities; 8 homes in Devens, MA in a project for MassDevelopment; 4 homes in Princeton, MA; 17 more homes in the Coppersmith Way development in Townsend, MA; 24 units in Harvard MA; and 4 units of positive energy housing are planned for the Roxbury, Highland Street site for the Boston Redevelopment Authority.

The cost to get to zero energy has been brought down to $3 per square foot over a stretch code home with a leased PV system. At these prices, the zero energy homes can spread fast throughout Massachusetts and other states with Solar Renewable Energy Credits. It is Transformations goal to help speed this process. The typical home saves about 60% of its energy in the shell, appliances, lighting, hot water, etc. The other 40% or more is made up though the PV.

The Groton features a 7.14 kW PV system that is integrated into the surface plane of the roof for a pleasing aesthetic. We attained the look of BIPV without the cost! The roof under the PV system was recessed 8” inches to accomplish this. Black framed mono-crystalline panels further this curb appeal.

A Navien 180 instantaneous gas fired hot water heater was used in place of any solar thermal systems. It did not take up any roof space, cost $1,800 to install (as opposed to $8,500 for a solar thermal system) and used only about $43 worth gas over a 12 month period (36 Therms).
The ventilation system used was a Fantech 1504 Heat Recovery Ventilator. We exhausted the three bathrooms and supplied fresh air to the hallway on the second floor. This was done at less than half the price of the LifeBreath systems we used previously.

This “Groton” model home was cost effective to build, has excellent curb appeal and is vastly repeatable and scalable. It was built on speculation and sold for $359,900. The positive energy produced was about 1450 kW hours a year. This is enough energy to supply a plug in Prius a modest commute, 5 days a week, 50 weeks a year. With homes like these, we can solve the carbon emissions of the building sector and start to work on the transportation sector as well!

Click here to see the poster submitted for “The Groton.”

2011 Winner

Camden Friends Meetinghouse

The winner of NESEA’s annual Zero Net Energy Building Award offers not only energy efficiency, but ideally also comfort, affordability, reliability, and elegance. Congratulations to everyone involved in this project.

Location: Camden, DE
Architect:Re:Vision Architecture, Mike Cronomiz, designer and project manager
Scott Kelly, principal in charge
Contractor: Camden, DEBoss Enterprises Inc.

High quality and integrated design in a community gathering space

The judges awarded first place to this Quaker Meeting House based largely on its high quality and integrated design. The Meeting and Social Hall sits adjacent to an historic 1805 Meeting House and serves as a community gathering space designed to complement the elegant simplicity of the historic Meeting House. After the first year, the new building’s solar collectors generated almost enough energy for both buildings combined. If the social hall were left to power itself, it would provide 150% of the power it consumed, making it a net positive building. In accepting the award, architect Scott Kelly indicated that he would use the cash grant to deploy solar panels on his firm’s office building.

Text from Zero Net Energy Award application:

The Camden Friends Meeting and Social Hall sits adjacent an historic 1805 Meeting House and serves the congregation as a community gathering space designed to complement the elegant simplicity and durability of the historic Meeting House. Spaces within the multi-function annex include a large social hall, catering kitchen, archival display, community outreach rooms, and restroom facilities.

To preserve the Meeting House as the crown jewel of the site, the new annex roofline steps down in a gesture of humility; lowering as it approaches the historic meeting house and outdoor worship space. A glass core at the main entrance to the annex allows visitors to see through the new annex to the historic Meeting House when approaching the building from the rear parking lot. The clean lines of the annex, which was clad with a rain screen of salvaged cypress, and metal roof, allow the Annex to float behind the historic meeting house without upstaging it.

The building’s form and layout are designed to take advantage of passive heating, cooling, and lighting. This passive design includes a tightly sealed thermal envelope with superior insulation. The exterior wall construction is of 2×6 wood studs, bio based foam insulation, with an additional layer of insulation applied to the exterior sheathing. A rain screen keeps the water on the outside of the building and reduces the risk of condensation on the interior. The roof is constructed of structurally insulated panels (SIPS) with an average R value of 48.

Through careful design and detailing, the building starts with a low energy load. Supplemental heat is provided by a closed-loop ground source heat pump system and power by a 12Kw photovoltaic array. After the first year, the new building’s solar collectors generated almost enough energy for both buildings, leaving only 188 kW provided by the local utility company for the entire complex. If the social hall was left to power itself, it would provide 150% of the power it consumed, making it a net positive building. Equally exciting, the building exceeded its predicted energy model in both energy reduction as well as water consumption through careful operations. In terms of water, a 2,000 gallon cistern collects rainwater and stores if for use in flushing toilets and irrigation.

By design, the building is intended to have the warmth and comfort of a home. At the same time, it needs to stand up to the intensive use that comes from accommodating large groups. In this way, the building straddles the residential and commercial sectors. While the 2,864 sf building is institutional in its use, its materiality, systems, and construction methods are all applicable on both the residential and commercial scale. Camden shows that net-positive buildings are feasible for homeowners, businesses, and non-profits who have this goal.”

Click here to see the poster submitted with the Camden Friends Meeting House application.

2011 Runners-up

More models of efficiency

More models of efficiency

The Putney School Field House, Putney, VT
Kraus-Fabel Renovation, Amherst, MA
Eliakim’s Way, West Tisbury, MA
The Groton, Townsend, MA

The Putney School Field House

Any building that meets the rigorous criteria to even be considered for NESEA’s annual Zero Net Energy Building Award deserves a shout-out. These runners-up, too, are showing us the way to a sustainable built environment. They have won our admiration, if not our prize.

Knox/Thompson Residence Charlotte, VT
Livermore Home deep energy retrofit Gloucester, MA
Moomaw House Williamstown, MA
The Putney School Field House Putney, VT
Shepler Residence New Paltz, NY


Knox/Thompson Residence

Location: Charlotte, VT
Owners: Katherine Knox and James Brian Thompson, Faith and Lark Thompson
Architect: Bill Hutchins, Helicon Works
Builder: Jim Huntington, New England House Wrights
Energy consultant/installer: Kirk Herander, Vermont Solar Engineering

An off-grid farmhouse inspired by NESEA’s Green Buildings Open House

It was our intention when we started this project to create a Vermont country farmhouse. We purchased the 45 acre parcel of land the house is located on in 2001. The land previously was a large farm and our parcel was segmented into two portions, approximately 35 acres of meadow and 10 acres of woodland. We built our house in the northwest corner of the meadow for a number of reasons. We could take advantage of the woodland to our north. This serves as a wind block for the cold northwest winds that happen in Vermont in the winter months. In addition there is a hill located just 300 feet from the house site and is the highest point on our land which is an ideal spot for a wind generator. To our south, east, and west we enjoy a lovely pastoral view of the rolling terrain. We also enjoy views of Camels Hump mountain, Mt. Philo, and portions of the Adirondacks.

As a consequence of building in this spot, we were at least a half mile from the nearest utility. The picture above is taken from the road and estimates to bring utilities that far off the beaten path were eye opening to say the least. Subsequently we investigated using renewable energy to provide electricity for our home. We did research on using renewable energy and the cost associated with those. We went on the “Solar Tour” that year and discovered that people did live off electricity generated by their own system. Using both PV and a wind generator to generate electricity would seem to be the best arrangement for this northern climate. We made our decision to go with renewable energy to power our home, we would use a wood stove for heat, and propane for cooking, heating our water, and other items.

Project Design: Initial plans and architectural design for the house was completed by Bill Hutchins of Helicon Works. His ideas consist of simple building forms that are beautifully composed. Thin clap-board siding is used with trim to define windows, doors, and entrances. The informal entry to the house consists of a Mud Room and serves as a link between the garage and house. An open floor plan on the first floor consists of a farmhouse kitchen, and a main living space that form a nurturing center of the house. The woodstove is positioned in the center of the main living space and provides warmth in the colder months. The house is positioned along the east west axis with a total of twenty windows that face south. The house can thought of as a sundial, with each room receiving it’s appropriate light. This enables us to use the light from the sun for most of our lighting during the daylight hours. Our PV array is fixed to the garage roof and points 194 degrees south. We consider the house to be well insulated and it takes advantage of passive solar gain. The highest efficiency lighting and appliances were used throughout our house. The house has been Certified Energy Star Rated 5 Star by the Vermont Energy Investment Corporation.”

Click here to see the poster submitted with the Knox/Thompson Residence application.


Livermore Home deep energy retrofit

COME SEE US ON OCTOBER 13TH DURING GREEN BUILDINGS OPEN HOUSE: Click HERE!

Location: Gloucester, MA
Project designer/owner: John Livermore
Engineer: Marc Rosenbaum, PE
Lead Carpenter: Caleb Ewing
Project assistant: Bill Hallaren

Taking personal responsibility for climate change—on $50,000

The motivation for taking action to reduce our family’s carbon footprint was the understanding that carbon emissions need to be reduced by about 90% by 2030 in order to stabilize the earth’s climate, and the realization that I needed to take personal responsibility for reducing our family’s emissions. Also, I’d been in the energy efficiency business for over 20 years and felt it was time to walk the talk, taking everything I’d learned about building science over the years and applying it toward retrofitting my own house.

The purpose of performing the deep energy retrofit and renewable energy installations on the Livermore residence was to demonstrate what can be done to reduce the carbon footprint of a suburban homeowner on a budget of approximately $50,000. The overall goal was to reduce the home’s carbon footprint by 100%, and in doing so to help others by changing the current paradigm of what is possible.

The retrofit strategy has struck a balance between three key objectives:

  1. Make it affordable
  2. Make it feasible (use off-the-shelf technologies)
  3. Make it repeatable

The house, located in Gloucester, Massachusetts, was built in 1972 and had poor energy specifications, including: Extreme air leakage (3,400cfm50), R-19 in attic, R-13 in walls, single-pane windows. Our retrofit philosophy was to reduce the building loads dramatically and then use solar energy systems to provide as much renewable energy as possible.

Key design features of the retrofit project include:

  • Larsen truss wall framing system to allow installation of 5 inches of closed-cell foam (R-30).
  • Gable roof extensions.
  • Innovative chimney insulation system.
  • Innovative basement floor and foundation wall insulation system.
  • Dramatic air leakage reduction (to 500cfm50).
  • R-76 attic insulation with radiant barrier.
  • Triple-pane, low-E, argon, foam-filled fiberglass frame windows.
  • 4.3 kilowatt photovoltaic system provides 186% of annual electricity needs.
  • 3-panel solar hot water system provides over 70% of annual hot water needs.

Other energy features of house include:

  • All LED and CFL lighting
  • All Energy Star appliances
  • Small Danish woodstove heats the entire house
  • 1.125 GPM showerhead
  • High-performance bath fan with 24-hour programmable controller

During the project, the Livermore house turned into a laboratory for carbon reduction strategies. The most significant behavioral modification has been hanging up clothes to dry, which has allowed dryer use to be eliminated and has resulted in approximately a 15% reduction in annual electricity usage.

The non-energy benefits of the project have been numerous and significant, including:

  • Higher comfort levels
  • Fewer colds and viruses
  • More durable home

The house has participated in the NESEA Green Buildings tour each year since 2009.

For more information, visit www.OnThePathToSustainability.com

Click here to see the poster submitted with the Livermore Deep Energy Retrofit application.


Moomaw House

Location: Williamstown MA
Owners: Bill and Margot Moomaw
Architect: Coldham & Hartman Architects
Engineer: Marc Rosenbaum, PE

Vernacular, low-impact building for the 21st century

The Moomaws desired first and foremost to make minimal impact on the natural ecosystem of their 14 acres, which contained fields, woods, and a one-acre pond that was home to wildlife and migrating species. They wanted a house for the 21st century that resonated with the natural site, and was compatible with vernacular building. The roof angles, the barn-red garage and shed, the rock walls fashioned of stones from excavation, clapboards, and trim were conscious decisions to blend with the 19thcentury agrarian tradition.

Initially they specified a highly energy efficient design using as much renewable energy and as little fossil fuel as possible. From their design team, architect Coldham and engineer Rosenbaum, they learned it would be possible, but a stretch, to achieve zero-net energy in their climate zone (7500-8000 heating degree days). During the design phase the team modeled various options for insulation, windows and energy consumption. Their contractor, Steve Haskins, embraced the concept and gave meticulous attention to insulation and air sealing.

Bill was enthusiastic about pursuing ZNE, but his wife Margot was more dubious, fearing they would compromise aesthetics to achieve the energy goal. After 2 years planning, 15 months construction, and two years of monitoring and modifying systems, they are pleased to achieve net-zero energy in a home that is beautiful and eminently livable. The 2200 square foot house was designed so the owners could work from home and accommodate numerous visitors. The couple hopes to live there for the remainder of their days. The first floor master bedroom and bathroom are wheel chair accessible. Adjacent to the main house and connected by a screen porch is a 460 square foot guesthouse for family and friends.

A long south façade provides passive solar heating. Half of the triple pane, argon-filled low E windows (U=.19) with high solar heat gain glass face south. In summer the roof overhang shades these windows. Only 15% of the glass is on the north side of the house, with the remainder divided between east and west. The location of windows optimizes day lighting.

The house utilizes a grid-connected 7.3-kilowatt PV array. Heat and hot water are provided by a 2.8-ton ground source heat pump that draws on the earth’s stored heat through 1350′ of horizontal loops. Radiant floor heating provides an exceptional degree of comfort. The house has a heat recovery ventilation system, and a Powerpipe to capture heat from shower drain water. The house is cooled in summer by natural ventilation and ceiling fans (no AC). Application specific artificial lighting is supplied by a combination of fluorescent, CFL and xenon/halogen on dimmer switches. Appliances were selected for low energy consumption (exceeding Energy Star standards). Renewable electricity is purchased from the grid as needed.

To the extent possible, materials were sourced from within 500 miles, and were chosen for recycled content (cellulose, TREX), durability (Hardiboard, standing seam metal roof, fiberglass framed windows), low environmental impact (PEX and ABS pipe, low VOC paints, native plants). New England hardwoods were chosen for flooring, kitchen cabinets, and built-ins (cherry harvested on the property). Siding for the garage and shed is local pine from managed woodlots. Upon completion, the house merited LEED Gold certification.

Click here to see the poster submitted with the Moomaw residence application.


The Putney School Field House

Location: Putney, VT
Architects: Maclay Architects

Showing students that sustainability is possible—and beautiful

This is not just a gym…We want this to be a place where our students can learn about being environmentally responsible, so that later in life, when they are making choices, they can say, ‘It’s possible. Our gym at school did it this way’.”- Randy Smith, Putney School

The Putney School is a progressive, college preparatory school located in rural southern Vermont. In addition to classroom buildings, the campus includes a working 500-acre farm. The School’s vision for a field house was one that would support a long tradition of excellence in sports programs and serve as a central gathering space for students, while meeting aggressive sustainability goals.

The two-story building features an on-site 36.8-kilowatt solar photovoltaic system, energy-efficient lighting with daylight and occupancy sensors, composting toilets, natural lighting, and earth- and human-friendly materials throughout. The first floor features a gym, a rock climbing wall, ski-waxing room, mechanical room and storage. The second floor, which serves as the central gathering space, includes bleachers that overlook the gym space, offices, locker rooms, and flex space for wellness and strength conditioning activities.

The team assessed five options consistent with the overall vision, including a Base Building Model, a High-Performance model, a Micro-load model, Carbon-neutral building; and a Net-Zero building model. The construction and operating costs for each were carefully studied, with estimates ranging from $3.5 to $5 million. Projected first year energy costs ranged from $22,500 / year to $1,200 / year. Estimated total CO2 emissions ranged from 130,000 LBs/year to 0LBs/year The net-zero option gained final approval, demonstrating how upfront investments in a super-insulated envelope, renewable energy and advanced systems create long-term predictability in future energy costs.

Super-insulation was installed and extensive air sealing was completed on the facility. To reduce heating energy use by 77% compared to the ASHRAE Standard 90.1-2007 baseline building (Appendix G.), the following high insulation levels were used: R-60 roof, R-45 walls above grade, R-20 slabs, R-20 foundation walls below grade and R-5 windows. We achieved a very low tested air leakage rate of 0.065 cfm/sq ft. of building shell at 50 pascals test pressure (0.065 cfm-50/sq.ft. shell) or 1,625cfm-50 total air leakage rate. We attribute the low air leakage to careful envelope design and execution.

Mechanical systems considered for the building included both ground-source and air-source heat pumps. The selected optimal system was an air source heat pump, as cost was the determining factor. To achieve the zero energy goal, investment in renewable energy sources was also required. To maximize performance and obtain long-term value, 36.8 kW of solar tracking collectors were installed to the north of the Field House.

Construction on the Putney School Field House began in 2007 and was completed in October 2010. The 17,500 square foot Field House is New England’s first net-zero athletic building and anticipates LEED Platinum certification from the U.S. Green Building Council.

Click here to see the poster submitted with the Putney School Fieldhouse application.


Shepler Residence

Location: New Paltz, New York
Owner: David Shepler
Builder: Greenhill Contracting

A plan for a 25-home net-zero community gets started

My home at 18 Cooper St. in New Paltz, New York, is the first of seven zero-energy (ZE) homes built by Greenhill Contracting in an attempt to create a 25-home ZE community (called Green Acres – www.greenacresnewpaltz.com). What sets this home apart from individual custom ZE homes built elsewhere is the proven repeatability of the model and a desire to maintain comfort along with performance. The other four occupied Green Acres homes have either already achieved ZE or are well on their way (5 of 7 are currently occupied). The success of my home-surpassing its ZE goal-is proving the repeatable approach to ZE construction with off-the-shelf technologies including PV, geothermal heating and cooling, and a high-performance envelope anchored by insulated concrete forms.

Envelope – All walls of the three-floor home, from foundation to roof, are built with insulated concrete forms (R-21 boosted by thermal mass effects). The slab is fully insulated with double-stacked R-20 rigid foam. The roof completes the tightly sealed envelope with 14″ of open-cell foam (R-50). The 3,237 sqft home includes a walk-out basement with generous natural light, superior insulation and ventilation.

Geothermal Heating and Cooling – A ground source heat pump (GSHP) provides all the heating and cooling needs of my home, requiring far less electricity than more conventional systems. My WaterFurnace GSHP uses a closed loop installed in a 499-ft vertical well.

Photovoltaic System (PV) – Although the home was sized to achieve ZE with an 8 kW system, I chose to install a full 10 kW in order to have extra capacity to accommodate an all-electric vehicle in the future. The SunPower system uses two 5 kW inverters installed in the mechanical room in the basement.

Windows, Light, and Appliances – I had a personal desire to maximize the natural light in the house without compromising the ZE pursuit. All windows are triple-paned, krypton-filled rated at U-value 0.22 or better. The true-solar-south facing side receives the largest share of windows to take advantage of passive solar effects, while the north side has the fewest. Rarely must a bulb be turned on during daytime due to the abundance of natural light. The kitchen uses nothing but LED lighting and the rest of the home uses CFLs. All appliances in the home (including a second full refrigerator and electric induction stove for a live-in tenant) are high performance, Energy Star approved, and the entertainment center is switched at the wall to eliminate phantom loads.

Other Notes – Although I installed a modern woodstove for aesthetic reasons, I have not used it, allowing me to fully evaluate the home without it. My living habits are typical: I use the dryer for my laundry and keep the home comfortable (69˚F winter, 75˚F summer). My LEED-Silver home has many comfort features: granite countertops, floating stairs, deep sills, under-lit cable rails, high-end cabinets, dual-flush toilets, radiant-heat floors in master bath, and vaulted ceiling.”

Click here to read an article from Solar Today about this project.

Click here to see the poster submitted with the Shepler residence application.

2010 Winner

Montague Urban Homestead

The winner of NESEA’s annual Zero Net Energy Building Award offers not only energy efficiency, but ideally also comfort, affordability, reliability, and elegance. Congratulations to everyone involved in this project.

Location: Montague, MA
Owner/designer: Doug Stephens and Tina Clarke
Contractor: Bick Corsa

 

 

 

 

2010 Runners-up

More models of efficiency

Any building that meets the rigorous criteria to even be considered for NESEA’s annual Zero Net Energy Building Award deserves a shout-out. These runners-up, too, are showing us the way to a sustainable built environment. They won our admiration, if not our prize.

BrightBuilt Barn

Location: Rockport, ME
Owner: Keith Collins
Architect: Kaplan Thompson Architects
Info: www.BrightBuiltBarn.com

Hagadorn Residence

Location: Northampton, MA
Owner: Caroline Hagadorn
Architect: Kraus-Fitch Architects

Hollabaugh House

Location: Lebanon, NJ
Owner: Margaret Hollabaugh

2009 Winner

Trailblazer: Maharam Residence

We unveiled the Zero Net Energy Building Award in 2007, but it wasn’t until 2009 that an applicant delivered the goods. Congratulations to everyone involved in the Maharam Residence.
Location: Charlotte, VT
Architect: David Pill, Pill-Maharam Architects
Contractor: Jim Huntington, New England Housewrights