RDI, with the help of many partners, is building a village of twenty Near Zero Net Energy homes near the center of Greenfield, MA. Eleven of the homes are being built for low-income buyers, five are designated for moderate-income buyers, and two will be sold on the open market.

In addition two homes will be fully accessible for people in wheelchairs. These two homes will be rented to people with physical disabilities. All twenty homes are visitable by people in wheelchairs.

Bill Austin and Chris Farley of Austin Design along with Robb Aldrich of Steven Winter Associates have worked closely with RDI to ensure that the homes meet our stringent energy efficiency requirements. Steven Winter Associates and the Center for Environmental Technology are working with RDI to fulfill the requirements for ENERGY STAR qualification and LEED® for Homes certification at the Gold, or possibly Platinum, level.

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Near Zero Net Energy
Near Zero Net Energy is a term that refers to buildings that produce almost as much energy as they use. The primary techniques used in the Wisdom Way Solar Village homes are those that start by reducing the heating, cooling, and electrical loads. A three-bedroom home is modeled to have a design heat load of 12,600 Btu/h when the temperature is 2° F outside. Key three-bedroom home features, which are very similar in the two and four bedroom homes, are:

• A small footprint with an open floor plan (1392 square feet of conditioned space above an unconditioned full basement);
• A southern orientation with a 3.4 kW photovoltaic and a 87 sq. ft. solar hot water system;
• A very tight building envelope;
• Recycled blown-in dry cellulose encircling the building envelope:
  

  • 12 inches in the offset double 2x4 walls for R-42;
  • 14 inches  in the ceilings for R-52;
  • 11 inches in the basement ceilings for R-38.
• Very high efficiency windows on the north, east, and west sides of the homes with a U-value of 0.18, a Solar Heat Gain Coefficient (SHGC) of .26, and a Visible Light Transmission (VLT) of 0.42.
• High efficiency windows on the south sides of the homes with a U-value of 0.26, a Solar Heat Gain Coefficient (SHGC) of .36, and a Visible Light Transmission (VLT) of 0.53.
• Continuous 50 CFM exhaust ventilation;
• ENERGY STAR refrigerator, dishwasher, and clothes washer (plus natural gas cook stove and dryer);
• Compact fluorescent light bulbs throughout;
• On-demand natural gas water heater as back up to solar hot water system;
• A sealed combustion Monitor room heater located in the central living area on the first floor (no fossil fuel based central heating system is necessary);
• No air conditioning;
• A unique air distribution system designed to move air and heat from the first floor to the second floor bedrooms; the ducts for this system as well as all of the vent fans will be sealed with mastic.