Northeast

Summary:

Rural Development Incorporated, with the help of many partners, is building a village of twenty Near Zero Net Energy homes near the center of Greenfield, MA. Eleven homes are being built for low-income buyers, five 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 and rented to people with physical disabilities. The first two homes are occupied and achieved LEED Platinum certification. Ten homes are sold; the other 10 will be sold through a buyer's lottery. Net Zero Energy elements include: southern orientation with a 3.4 kW photovoltaic and a 87 square foot solar hot water system, a small footprint (1392 SF) with an open floor plan, tight building envelope, high efficiency windows, Energy Star appliances, sealed combustion Monitor room heater.

The homes are earning Home Energy Rating System (HERS) index scores of between 7 and 17, where a 0 score would indicate zero net energy use and a 100 represents a standard home. Thus far, residents are achieving near-zero net energy.

Summary:

Single family, 6,200 SF house split into two sections--a living bar and a sleeping bar. During low occupancy times, the living bar, which includes living and dining areas and a master bedroom, is used and the sleeping bar, which houses guest sleeping areas, is shut down to save energy. The house was built with double stud framing and foam insulation level R-12. Ground source heat pumps supply heating/cooling and an HRV is used for ventilation. An 11.7 kW PV rooftop array supplies electricity. As of 2013, the house requires an expanded solar electric system to offset additional consumption due to unforeseen occupant behavior.

Summary:

The 3,400 SF, 1978 ranch house was renovated to be zero net energy and is LEED Platinum certified. The original siding was replaced with structural insulated panels (SIPs) and closed-cell spray foam insulation achieving R-52 walls, R-73 roof. A ground source heat pump provides heat distributed by an in-floor system. Other features include triple-glazed, low-e fiberglass windows, an HRV, and solar hot water heater. A 7.5 kW roof-mounted PV system meets electricity needs. In 2009, the home produced 1,732 kWh more electricity than it used.

Summary:

Community will be comprised of 25 zero net energy single-family houses sized from 3,000-4,000 SF in New York's Hudson Valley. An 8 kW solar PV system supplies electricity for each home with heating/cooling from ground source heat pumps. Energy efficiency features include passive solar design, insulated concrete form (ICF) construction, triple paned windows, and a heat recovery ventilator. As of November 2011, five houses have been completed and occupied with two more under construction. The first three houses are LEED certified, at silver and gold levels. Of the three, two houses achieved zero net energy use from 2009-2011.

Summary:

This off-grid 1,600 SF SIP construction house features passive solar design and radiant heat derived from a thermal mass storage system. Daylighting is supplemented with a covered walkway connecting the front door and detached garage to mitigate solar gain. The garage roof supports a 5.5kW PV array and solar hot water panels. A 6-foot deep below-grade sand bed contained with insulated concrete form (ICF) walls stores the heat from the glycol- filled piping that runs through it from the solar hot water system. It is transferred to slab radiant floors by a computer-controlled system.

Performance monitoring over 2 heating seasons shows that thermal storage runs out after January and the home owners need to supplement with ~ 0.75 gallons of propane/day for the main house. Increasing the mass storage volume and doubling the thickness of the ICF walls of the sand bed is expected to prolong the thermal energy storage and bring the system closer to ZNE through the winter months.