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

It is a house with a roof that generates electricity, a heating system that extracts heat from 400 feet below the ground, walls that store heat during the day and release it at night, windows that allow more heat to enter than escape, and fireplaces that draw combustion air from the outside. It is called Impact 2000, and money was no object in building it in Brookline, Mass. The house will be put up for sale next month at current market value, which is estimated to be $500 000.