A contemporary house that will be able to rely on solar energy without using special equipment is nearing completion in the Gaithersburg area.

It was designed by John P. Ross, and architecture student at the University of Maryland, and Alan Trellis, who is building the house with William Watkins. The builders have a $12,000 demonstration grant from the Department of Housing and Urban Development, which is encouraging the creation of passive solar heating design. The Gaithersburg house will maximize thermal gain and minimize heat loss through windows and sliding glass doors.

In addition to windows and door with triple gazing, the house has movable, translucent panels on the east and west sides. They admit light and heat by day and are to be closed at night to seal in the warmth.

"The translucent material will filter hard, direct sunlight and cause it to be diffused and softened," said Trellis, who was formerly director of technical services for the National Association of Home Builders.

Watkins, an engineer, said that the passive solar featurs of the four-bedroom house may supply nearly half of the heat required to make the house comfortable. While the south-facing windows were placed to admit solar heat, there are roof overhangs and shadings to "let the sun in when you want it and keep it out when you don't," he said.

The house also has a two-story "greenhouse" area in the center to collect heat. Heat will be blown into a concrete block storage area and then directed through a duct system to the second floor of the house. An electric heat pump system will provide back-up heating.

"A sensor automatically unrolls an insulating curtain in the greenhouse at night and rolls it up in the morning," Trellis said. He added that the passive solar features increased the cost of construction by more than $1.25 a square foot but that savings in heating and cooling costs are expected to be reduced by about 40 percent.

Trellis and Watkins, who sold the $16i,000 house to Merle and Sue Uskievich of Rockville, will show it to the public tomorrow and next Saturday and Sunday from 1 to 5 p.m. to reach the house from Rte. I-270 go east on Shady Grove Road, right on Muncaster Mill Road, left on Muncaster Road for about three miles to Granby Road, turn left. The frame house is on the left side of the road. CAPTION: Picture, South-facing windows are a major feature of this solar-heated house under construction near Gaithersburg. By Margaret Thomas - the Washington Post