I recently attended a Certified Passive House Training program at Yestermorrow Design/Build School. Along with the building science education, the computer modeling in Wufi and Therm, I really enjoyed getting to know the other people there. So, who attends an 8-day in-person course in Waitsfield VT? Energy geeks. Mostly architects, some HERS raters, students and two mechanical engineers.
As one of the two mechanical engineers there, and an energy geek, the Passive House (PH) standard appeals to me because unlike other green building standards, it’s performance based. Where other standards can feel restrictive, PH design is flexible – a project can achieve certification as long as it meets the energy and airtightness goals.
And those goals are no joke. To meet the PHIUS+ 2015 standards, a single family passive house in Boston could be looking at insulation values of R-43 for the wall, R-70 for the roof and R-20 below the slab. (The R-Values go way down in multifamily, because the surface-to-volume ratio improves.) The design principals used to meet the standards are: continuous insulation, air tightness, optimizing solar gains, heat recovery ventilation and minimized mechanical systems.
The mechanical systems approach for PH is refreshing: simpler is better. While the classical approach to PH uses space heating through ventilation ducts, this is not required, and in most cases it isn’t practical. Decoupling the heating and ventilations systems makes sense, because it keeps with the simpler is better design philosophy and because the demands on the systems are totally independent (ventilation is required at all times, heat isn’t).
My take-away from the course was that while the primary goals of the PH standard are energy efficiency, the results are greater durability, occupant health and comfort. By controlling the movement of heat, air, moisture and bulk water within the building, the outcome is a building that will last for generations.
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Ted is a mechanical engineer who understands building enclosures with a passion for improving building performance. He first attended BE in 2015 as a NESEA intern.
Hi Ted,
Enjoyed reading this as a resident of Vermont and one time instructor at Yestermorrow. I taught introduction to furniture making. For the last 12 years I have run a a window weatherization company in Vermont called Opensash. You can check it out on line. Opensash.com I applaud the simple is better idea in design, but am search for those who have identified the problem of modern repairability. We cannot reduce our carbon footprint if our net-zero infrastructure needs to be replaced every 30 years. I am keenly aware of the high peformanance windows that have a short life span and no easy way to fix or maintain them. This on top of the lack of attention being paid to the existing homes that 80% of the population lives who cannot afford high performance windows makes me think we need to redirect our attention to upgrading existing homes in an affordable repairable manner to make a dent in our carbon foot print. I am looking for anyone who is taking on planned obselescense as a big climate change issue. Thanks Chris