Some down-to-earth advantages in underground houses

Any reservations Stuart Campbell may have had about living underground vanished the moment he stepped into Baldtop Dugout, the home of architect Don Metz, which is set snugly into a Lyme, N.H., hillside.

The carpenter-turned-ski instructor, who is a writer on a wide range of topics from earthworms to hot-dog skiing, was already partway sold on earth-sheltered living, for some very sound economic reasons. In his region, earth-sheltered homes are cheap to heat and cooling costs are nonexistent.

Maintenance costs are cut, too, because you don't to paint the exterior walls every few years if those walls are buried underground. Because the roof is covered with sod, the grass continually renews itself. It may need mowing once in a while but it will never need reshingling.

Earth-sheltered homes are also very quiet (even when sited alongside a freeway), private, and are more immune than aboveground dwellings to all natural disasters except floods.

But who really wants to live like a mole?

In Baldtop Dugout, Mr. Campbell found you don't have to. The interior of a well-designed underground home is light, bright, airy, and well ventilated. It also can appear as conventional as any aboveground structure. It is only in the exterior appearance that the differences are obvious.

A good earth-sheltered dwelling disturbs the surrounding landscape very little, and you shouldn't realize you near one until you are almost alongside it.

Stu Campbell expects his home, now under construction here, to "disappear altogether" when viewed from the air. His will have a sod- covered roof with a planting of small shrubs.

"I may even put the salad garden up there, too," he says.

As a father, Mr. Campbell has frequently tucked his young children into bed. He feels strongly that people should do the same thing with their houses -- tuck them snugly into the side of a hill, where they are largely surrounded by a blanket of earth that remains at a constant 55 degrees F. a few feet below the surface. Thus, the warming and cooling advantages are obvious.

It takes a whole lot less energy to warm up a house that is surrounded by 55 -degree F. temperatures than one that is exposed to, say, zero and lower air temperatures in the wintertime. And if the wind is blowing, the earth-sheltered home is at a still greater advantage.

Similarly, when temperatures soar up and beyond the comfort zone outside, this same bank of stable cool soil that warmed you in winter now takes the bite out of the air-conditioning bill by absorbing the heat from the air inside the house. So, while heating costs are minimal and cooling costs zero in a properly sited Northern home, an earth-sheltered home in the South should have drastically lower cooling bills in summer and zero heating costs in winter. The sun streaming through the south-facing windows, added to the heat generated by cooking, lights, TV sets, etc., would be adequate on all but a few rare occasions.

The University of Minnesota's recently built underground bookstore is so remarkably energy-efficient that its lights and people generate enough heat to maintain a 70-degree F. indoor temperature until the air outdoors gets down to minus 20 degrees F. Only then does the active solar heating system come into play.

Don Metz, owner of the underground home that so excited Mr. Campbell, and designer of several other, similar homes, suggests that heating and cooling costs of the earth-sheltered dwelling should range from one-half down to a third of the cost of an aboveground home.

Malcolm Wells, another pioneer designer and recongnized expert in the field, tells of a home he built for Mr. and Mrs. Robert Homan near Philadelphia in his book, "Underground Designs":

"All through the winter of '77 we waited for word from the Homans. January. February. March. . . . Finally, Bob visited us, and we all said, 'Well?'

"'We didn't use any auxiliary heat at all.'

"So we had our first real proof that under record conditions, solar heat and earth cover is a powerful combination even in the Northeastern part of the US."

It is figures and facts such as these that make Mr. Campbell say: "We like to think our prehistoric ancestors were smart enough to move out of their caves. Now there are those who say that wasn't such a smart move after all."

But what about cost? Isn't an earth-sheltered home vastly more expensive to build than a conventional one? Mr. Campbell asked the same question when he began the extensive research that led to his just published book, "The Underground House Book" (Garden Way, $9.95). The answer is an emphatic no, although in very few instances can they be considered cheap.

Don Metz contends that underground- home costs would run about 10 percent above conventional home costs but that the extra construction costs would be readily paid back by the energy savings.

Conversely, John Barnard of a Massachusetts company, Ecology House, promotes an atrium-type (courtyard in the center of the building) earth-home that he contends can run at 25 percent under conventional building costs.

Then there's Rob Roy, a designer-builder whose own 900-square-foot "Log-End Cave" home near West Chazy, N.Y., cost $8,000.

No special construction skills are required for underground houses. Any competent builder will do a satisfactory job. But not just any architect, Mr. Campbell warns.

"find someone familiar with the intracacies of underground building," he declares.

As yet, standard plans for underground homes are rare, but one day they will doubtless be as commonplace as are plans for aboveground dwellings. If you're interested, consult an architect who knows the structural requirements of a building that must resist the pressure of the surrounding soil and support a roof that is covered with four feet of wet snow. Waterproofing and drainage are also vital, as is proper ventilation.

It has been said, with some measure of truth, the architects and builders do not control the style of buildings, but rather, the financial institutions do.

Bankers are primarily interested in a secure loan. If the borrower defaults, will the house sell readily? is the first answer a banker seeks. Innovative designs, therefore, are looked on with suspicion, and at this stage the underground home can be looked on as innovative.

But, says Mr. Campbell of the would-be owner of an earth-sheltered home seeking mortgage money: "Your ace in the hole will be to point out what the banks already know: that energy costs will surely rise faster than incomes during the next few years.

"Life-cycle costs, which include expenses as well as mortgages, are lowered considerably in an underground house."

Mar L. Korell, former executive assistant to the Federal Home Loan Board in Washington, expresses it this way: "With earth-sheltered homes having the potential to reduce energy costs 30 percent, 50 percent, even 80 percent, they should enjoy special favor as a way to reduce the risk to lender and owner alike of the monthly payment overload."

Meanwhile, there is some indication that insurance companies are looking favorably on earth-sheltered housing.

With less need for artificial heat, fires caused by faulty furnaces or overstoked wood stoves are less likely to take place. Moreover, because so much of the home is poured con" crete, there is less of it to catch on fire. Storm damage, too, would be much less likely to occur; and damage from frozen pipes would be virtually unknown.

At least two companies, State Farm Insurance and Safeco, according to Mr. Campbell, are considering 35 to 40 percent premium reductions for earth-sheltered houses.