Impact 2000: A place in the sun: Sponsored by Boston Edison as an energy-conservation experiment, this home in the suburbs was seen during its construction by public-television viewers across the United States

The Impact 2000 house was built by the Boston Edison Co. to demonstrate to the public state-of-the-art energy technologies and conservation techniques. The roof of the house is a junior power station. It has two photovoltaic arrays, each containing 12 modules mounted on the rafters. Each module is 4 by 6 ft and has 432 photovoltaic cells. The maximum power output from the arrays is 4.3 kilowatts. The DC electricity produced by the arrays is converted into AC by an inverter in the garage. The primary component in the solar hot water system is the solar collector. Also described is the house´s passive heating system, comprising a two-story sun space, several tons of internal concrete, and 440 sq ft of heat-mirror glass. To maintain air quality in this tightly sealed house, there is an air-to-air heat exchanger, which can replace all the air in the house about once every hour, but it is only turned on when needed. It has its own system of ducts and ventilators, separate from the heating and cooling system. This ensures thorough mixing of the air throughout the entire house.