Looking for the best ways to use heat pump water heaters efficiently, reliably, and without compromising comfort? So are we. In multifamily buildings around the Northeast, the speakers have investigated integrated, tank-type water heaters as well as larger, central heat pumps. Both have challenges, and speakers will present many examples of how NOT to use HPWHs in multifamily buildings. We are learning, however, and the technology is evolving. Systems using CO2 refrigerant are coming from overseas that appear to offer good performance even in cold weather. This session will include a review of the range of technologies currently available, discussions of applications and challenges, and our best take on best practices for heating water with heat pumps – now and in the future.