While special considerations were necessary in providing the heating and cooling systems for one of the first passive houses built in the U.S., mostly conventional materials were used for the building envelope. The key to the Bethesda, Md., home’s heating and cooling energy efficiency is that the home is airtight and the roof and walls are heavily insulated. In addition, fresh air drawn in is heated or cooled before it enters, reducing energy costs. The house was built to the Passive House Institute U.S. standard, and it consumes 90-percent less energy for heating and cooling compared with a conventionally built house of similar size.
PB Topical Ref
