FEBRUARY 1978, David and Jackie Wysong got their January heat bill: $450. It sent them running to architect John W. Rust and solar designer and builder Thomas Rust.

This January, the Wysong gas bill was $109 and their February bill $47, including hot water and cooking.

This is how the Wysongs moved down the hill and saved all that money.

The house and garden will be open on April 25, Alexandria's day on the Historic Garden Week in Virginia. (See Tour story below.)

Abaout 1918, Charles T. Nicholson built a handsome Edwardian style clapboard house atop a five acre hill in Alexandria. In 1950, his son, Dr. Charles T. Nicholson Jr., hired Robert Nelson Rust to build a fine brick house halfway down the hill on the family property.

Jackie Nicholson grew up in the brick house. When she married David Wysong, they bought her grandparents' house at the top of the hill and lived there for 12 years. In 1979-80, the Wysongs, sold the clapboard house and bought land from her father, further down the hill on the family estate. Following her family tradition, the Wysongs built a house of their time, incorporating, as her parents and grandparents before her, contemporary tastes and techniques. The Wysongs also followed a tradition in selecting Thomas and John Rust, sons of Robert Nelson Rust, as respectively builder and architect.

The architect, builder and owners began in August 1978 to decide what was to go in the house. Construction took about 13 months. The Wysongs moved in on Feb. 8, 1980.

The budget was $175,000 for the house (exclusive of land). The final total was something more than that, but under $200,000. The square footage is 3,000 finished, another 1,500 unfinished.

We came into the house across a bridge spanning a steep slope. The house is built downhill from the street. The bridge makes it possible for you to enter on the middle of the three floors.There are no windows on the street side, the cold north side of the house.

Inside the front door, a staircase goes up to the bedroom level or down to the living level. The entry and staircase hall is not heated. Doors at the top and bottom close off the staircase from the rest of the house. The hall acts as an airlock to keep cold outside air from coming into the house.

The main floor of the house, the living area, is divided into four smaller, separate rooms, instead of the one larger open-plan area that many people would have preferred. Jackie Wysong's explanation makes sense to anyone with children. The Wysongs have three: Mary, 13, David, 9, and Matthew, 4. "The difference in age means they have different interests, so we wanted a house where everyone could have some privacy for what they wanted to do," Jackie Wysong said.

Architect John Rust worked with the Wysongs on the floor plan by drawing what they called "bubbles" or activity areas, and then moving the circles around until the space fit the need. Linda Waddell, the interior designer, helped plan where the furniture was to go, so it wouldn't block heating grills. In many cases, John Rust planned niches for specific furniture.

At the base of the steps is the atrium dining room, the key to the house's passive solar heating system. The two-story insulated glass wall, about 20 feet high, faces due south. The sun warms its brick walls and flagstone floor (technically called a trombe effect). The masonry is a heat sink or storage area. After the sun goes down, the heat is reradiated into the room.

"When the atrium air temperature exceeds 70 to 80 degrees (depending on how it's set)," explained Tom Rust, "automatic dampers in the conventional heating system open to allow this excess heat to be distributed throughout the house." The late March day we were there, the atrium temperature was 74, though its thermostat was set at 60 and the outside temperature was 56.

A metallic gold shade rolls down at night to keep the heat in. "I'm very careful to let it down at dusk and open it before breakfast," Jackie Wysong explained. The shade's several fabric layers inflate when it's pulled down (and deflates when it's rolled up -- Jackie Wysong has mastered the trick of rolling it up slowly to allow it time to unpuff) to form a blanket of air insulation that seals against the wall. The shade was made by the Thermal Technology Corporation of Snowmass, Colo.

"We had a hard time finding them," said Tom Rust, "because every time we called them, they were out skiing." The Wysongs hope eventually to have enough money to install exterior roll-down shutters all over the south windows, for even more energy savings. Such blinds are made by Pease Company and Soleil as well as several others.

Unlike many glass walls, the Wysong wall does not overload the house's cooling system in the summer. A 3 1/2-foot overhang keeps the higher summer sun from coming in at all, so the masonry does not heat up. The hot air rises, Tom Rust points out, to the top of the atrium. The Wysongs open the doors to the north, which doesn't have direct sun, and at the upper level of the atrium to pull cool air through the house. In case that fails, a whole house fan in the top of the atrium pulls out the hot air.

A balcony on the second level overlooks the atrium. Plants on the first floor and balcony also help to humidify the air.

The room is simply furnished: a wonderful table (the leaves are self-storing in the middle of the table) from Jackie Wysong's mother, and chairs. China closets are built into the corners.

To the left of the atrium is the family room/kitchen. The aisle kitchen is tucked away in an alcove. "That was the first thing I told John," said Jackie Wysong. "We had such a big kitchen in our last house you could walk yourself silly between refrigerator and sink. I also wanted to keep everybody out of my way when I was cooking.

The kitchen has a counter separating it from the eating area with its table and benches. The Sub Zero refrigerators are not only built-in, but their doors are wood-clad to match the cabinets. Both kitchen and dining areas are on the north side. The 15-by-19-foot sitting area is on the south side, with a fireplace and a glass wall for light. Doors lead to the east screened-in porch.

A deck wraps around three sides of the house, to extend the living area from all the south rooms.

The 15-by-17-foot formal living room is at the other end of the house. Jackie Wysong has several pleasant old pieces of furniture from her family in here.

The fireplace is another Rust special. It's named the Count Rumsford fireplace after a man who lived about the same time as another fireplace designer, Benjamin Franklin (whose fireplace was actually a stove). Rumsford's design is shallow rather than deep, with the sides slanting toward a shorter back. Around the opening is a thick masonry back wall to hold the heat. On top of the chimney is a Chim-a-lator damper. "It works better than a damper at the fireplace level," said Tom Rust. "When you open a normal damper, the column of cold air in the chimney swooshes down. This damper keeps the house heat inside the building."

A cable drops down the chimney so you can open and close it. Rust points out the damper also keeps out squirrels and racoons. The damper itself is cheap, about $50, Rust said, but installation would be extra.

North of the living room is a peaceful library, making four separate places on the middle floor for entertainment solitude. A powder room is adjacent to the library. Though the room is small, a supergraphic by Color My World painter/designers brightens it up.

The ground floor is useful too," Jackie Wysong said. "The whole neighborhood roller-skates on the cement floor and paints down there." Sliding glass doors let in light to the ground floor. At the moment, it isn't heated, but there is a flue for a stove when they want to finish its 1,500-odd square feet.

Upstairs, the master bedroom also has a dressing room and its own bath. The canopied bed came from Wysong's 96-year-old grandmother. The Wysongs' daughter Mary has a walk-in closet, a built-in desk and a bookcase headboard bridging the twin beds. Her ice-skating trophies show off here. Matthew has a needlepoint picture of cars made by his mother. David's room has a skylight that's actually a Velux window that swings in to clean, and has brackets for outside and inside shades. A supergraphic, also by Color My World, brightens his room.

Outside the house, Southern Produce landscape architects of Alexandria planned and executed the planting with Jackie Wysong. On the advice of the Rusts, the trees on the south side are deciduous for summer shade and to let in the sun in the winter. Evergreens on the north help shield against the cold wind. The fee was $10,000, including sod and a year's guarantee on the planting, but not including the basketball goals, the work of David Wysong.

The house is heavily insulated with Fiberglass, rigid foam and an extra two inches of rigid foam thermal breaks at such places as sills, headers and concrete edges. Rust even sealed around where pipes and electrical conduit come into the house. All glass is insulated. The house has two gas furnaces, one in the basement, one in the attic for zoned heating and cooling. Provision has been made for installation of solar collectors on the roof later.

John and Tom Rust have worked on more than 12 solar homes and buildings and have five more in the design stage.

As we drove past the house on the road opposite, Jackie Wysong let down the shade so we could see the effect. It glittered like the gold it is supposed to save.