WISDOM WAY SOLAR VILLAGE
Location: Greenfield, Mass.
Cost: $159 per square foot (excluding site development)
Builder: Rural Development Inc., Turners Falls, Mass.
Architect: Austin Design, Colrain, Mass.
Developer: Rural Development, Inc.
With no central heating or air conditioning, the 10 duplexes of the Wisdom Way Solar Village rely on passive solar warmth and a gas-fired backup sealed combustion heater in the main living space to comfortably get residents through frigid New England winters. Opposing, operable windows allow for cross-ventilation in the summer.
Thanks to a tight building envelope, careful air sealing, and super-insulated walls, the two- to four-bedroom units stay warm while residents enjoy practically no heating bills.
Blown-in cellulose insulation provides R-values of 42 for walls and 52 for ceilings. High-efficiency windows on the north, east, and west side with U-values of 0.18 and SHGC of 0.26 trap heat inside, and an air distribution system helps move air and heat from the first floor to second-floor bedrooms.
Annual energy costs, including all utility fees, range from about $170 to $450, according to Jacqueline McCreanor of the projects architecture firm, Austin Design.
Each home is also outfitted with a 2.85 kW or 3.42 kW PV system and a solar hot water system with an on-demand backup water heater. A recent study by Steven Winter Associates found that the energy generated by the solar electric systems exceeded the electric energy used in most of the homes and that some of them had a net credit from the electric utility over the course of a year.
Other sustainable features:
--offset double 2x4 walls
--small footprints of 1,150 to 1,400 square feet
--locally harvested hardwood floors
--continuous 50-cfm ventilation