Energy efficiency goes into design of this new home

How would you like to own a house where the year-round temperature is a constant 68 degrees F. and costs almost nothing to heat? A dream? A gimmick? Not according to Eugene Leger, an architect, who has designed and built his own energy-efficient house to prove it.

The Leger house does not depend on any expensive roof solar system. It is a conventional 1,200-square-foot ranch house with no strange shapes, no massive heat-absorbent walls that face south, or columns of water in the living room.

Further, there is no wood-burning stove in the living room and no furnace in the basement.

How does Mr. Leger do it? By building a house that has airtight walls and by using massive insulation -- more than twice the amount in any average contemporary house.

The only heat sources are the gas stove in the kitchen, normal lighting, body heat from the occupants, and a backup of 14 feet of baseboard coils run off the hot-water heater for those who might prefer a little warmer temperature.

Mr. Leger built his house by following three criteria:

* That his house should be as energy-efficient as possible and at no additional maintenance cost to the owner.

* That it should use low-level technology wherever possible so as to reduce construction costs and make it possible for the average wage-earner to buy it.

* That it should avoid materials such as fiber glass, aluminum, or brick, which are energy-intensive to produce.

There are other experimental houses around which use the double-wall technique, but none that uses Mr. Leger's particular design, so far as he knows. The double outer wall, for example, is 10 inches thick. Each wall uses 2X4 studs, staggered and separated by a 2-inch gap to allow insulation to completely cover the studs so that no heat is transferred to the outside.

The outer of the two walls is lowered to the still plate, the joint carefully insulated in sealer.

Mr. Leger claims that this technique eliminates a major source of heat loss.

In place of plywood, he runs Styrofoam-brand sheeting on the outside of the house down to the base of the foundation, thus further reducing air loss.

Water pipes are brought under the foundation wall and up through the basement floor. Gas pipes come into the house through the wall but are tightly sealed in urethane insulation.

The gap between the two double outside walls is filled with wet cellulose and then covered with a vapor barrier.

By using roof trusses, Mr. Leger is able to complete the ceiling, inner walls , and oak floor to produce an unbroken airtight inner surface. Only then does he install interior dividing walls. Not only is this energy-efficient, he says, but it is actually less expensive to build in labor and materials.

The windows are double- or triple-glazed and two-thirds of them face south. Mr. Leger insists that this passive solar technique is merely common sense. Total window area is only 13 percent more than in the average house.

Other unusual features include hollow box beams that are stuffed with insulation rather than the more common solid header beams; heavily insulated steel front and back doors, connected to the living area through self-contained vestibules; and the entrance to the attic is placed in the front vestibule to prevent warm air from rising into the attic.

As much as 20 percent of heat loss normally occurs where electrical outlets and plumbing enter the house. Both enter the Leger house under the foundation.

Rather than make connections in the outer walls, Mr. Leger runs outlets from continuous electrical strips which are mounted flat against the walls of each room, therefore permitting maximum flexibility. cooking is by gas, while water is heated in the basement from a 40-gallon storage tank by a small Japanese water heater that can also supply backup heat, if needed.

In future houses Mr. Leger says he will install more-efficient water heaters that only heat the water actually required.

The major feature of the Leger house is that it is superinsulated.

Many people believe that additional insulation beyond a certain point becomes cost-inefficient. Mr. Leger disagrees, saying that fiber glass, for example, loses up to half its R value (insulating property) through "degrading" by winds penetrating the outer walls of normal homes.

Mr. Leger insulated with wet cellulose, made with recycled newspapers, up to R-60. Cellulose retains its insulating properties, he claims, does not cause moisture problems, and is less expensive to install. The attic has 9 inches of insulation but there is none in the basement or under the floors.

How does the house perform? In the first four months of 1979, when the average outside temperature was 33 degrees F. and backup heat was used, the gas bill came to $38.50. Since then tests have been run on the house by the Princeton Energy and Environmental Group.

Two other experimental houses in North America use many of the same techniques, but what sets the Leger house apart is that it can be built for only a few hundred dollars more than a conventional house. Builders seem to be generally skeptical, however. There are said to be no hidden costs that would substantially add to the construction price.

The cost of extra timber and insulation is more than offset by the absence of a furnace and by the simplified construction techniques.

Mr. Leger says he finds that most people, when they hear about the house, have many preconceptions and doubts. They assume, for instance, that an airtight house must be oppressive and tropical to live in. Humidity, however, has usually remained at a comfortable 60 percent and, when it has risen, the owner has either used a dehumidifier or simply opened the windows.

To avoid stale air and odors, Mr. Leger installed an air-to- air heat exchanger which costs $1 a month to run and draws the stale air out and brings in fresh air which is preheated through paper membranes.

Mr. Leger already has sold his prototype house and now is busy retrofitting another house which can be done either by adding an extra wall inside or out. Although it will probably cost more than adding solar collectors, Mr. Leger insists that over the years it will prove more economical. He insists that not every house can incorporate solar panels, either because of design or location.

Looking ahead, the New England architect says the goal should be to build houses that will truly conserve energy, cost little or nothing to heat, and which the average worker can afford to build, buy, and live in.