"Simple solar" might describe a New England house that already has proved it can conserve energy through a long, hard Massachusetts winter.

The house has no complex solar gear, but it was so carefully researched and planned that it captures almost every available ray of sun.

It was designed by Nancy Dingman, an architect who graduated from Harvard in 1973 and lives in Cambridge -- and the wife of the couple for whom the house was planned. The couple wanted for themselves and their small daughter an energy-saving house where they could enjoy privacy, outdoor life, gardening, cooking and indoor horticulture.

The year-old house is centered on 80 rolling acres of meadows and woodland in the Berkshire hills of western Massachusetts.

A Fisher wood-burning stove purchased for $495 is used to supply auxiliary heat, as well as for trash burning and some cooking.

One cold day last February, the inside temperature was 70 degrees with neither the furnace nor the wood stove in use.

What are the architectural features that make the house so energy efficient?

It is carefully positioned on the land to face true solar south, not magnetic south, so it could take full advantage of the sun's heat. All large windows face south or east. The small windows are on the north side, toward the direction of the prevailing wind.

No air conditioning is needed even onwarmest days of summer. When the small north windows are opened at the same time as the wide patio doors and larger windows on the south side, the natural wind dynamics and such that cool air is pulled through the house.

All windows and doors, including patio doors, three skylights and the "sun garden" windown greenhouse have double-pane, tightly sealed insulated glass, a necessary expense for getting the maximum use of solar heat.

In this case, the young wife read books on solar heating, talked to a solar consultant, and researched the available types of insulation and realted materials that would deliver the energy-saving features that she and her husband wanted.

After many conferences in which the husbands of the two also contributed, Dingman pulled all the information and ideas together into her plans for a two-story house with basement, three bedrooms and 2 1/2 baths.

The architect terms it a "contemporary house for a country setting," although it has a traditional New England saltbox roof. Its exterior is western red cedar left unfinished to weather naturally. Its cost was under $90,000.

It turned out to be an excellent example of an energy-efficient structure that inc orporates insulating glass windows and doors as integral parts of its design. The whole house acts as a passive solar collector, and no solar hardware is involved. The average monthly expenditure for oil (for furnace heat and hot water) from September 1977 through March 1978 was $27.33 -- the cost of 56 gallons of oil at 48.8 cents per gallon.

The roof is insulated with two layers of six-inch-thick fiber glass, for a total of one foot of insulation (about double that found in the usual modern tract house).

A cross-section of the wall, from the inside, out would show first plasterboard, then a 3-mil "blanket" of polyethylene, then a six-inch layer of tongue-and-groove styrofoam sheathing, and then exterior siding of red cedar clapboards.

The one-inch-thick slate floor, laid over a five-inch-thick concrete slab in the 15-by-34-foot living-dining room, is designed to act as a "heat sink," which absorbs heat during sunny days and radiates it back into the house at night.

The pitch of the roof on the south side of the house is 45 degrees, designed for posible installation of a solar-collection unit (a sloped series of black panels that would face solar south). The owners consider such an installation unnecessary at this time.

There is a wood-and-oil-burning hot air furnace in the basement. If the wood, cut from hardwood trees on the property, burns out, the oil automatically turns on.

To make double use of furnace heat, a fan in the family room ceiling carries the hot air through a wall duct back down to the basement and blows it under the slate floor to add to "heat sink" effect.