Harry Hart, a Northern Virginia home builder, has completed six energy-efficient houses that cut fuel costs by as much as 80 percent.

Staff writer Thomas Grubisich described the Hart Development Corporation's activities in a story that appeared on Monday's Metro page.

It was an exciting story because it indicated that after thousands of years, man is finally learning to build a good, snug house. But there was also an undertone of disquietude in the story, and at first I couldn't quite put my finger on what caused it.

Shortly after noon on Monday, I phoned Hart and asked him whether he had heard any reaction to the Grubisich story. "Have I ever," he said with a sigh. "The phone has been ringing off the hook all morning."

"What kinds of people have been calling?" I asked. "People who say they don't believe you?"

"No," he said, "people who want to buy energy-efficient houses. There is an amazing amount of interest in houses designed to save energy, because energy costs are so high now."

"Heck, I was interested in improved home construction even before fuel costs got so high," I said. "I'm allergic to cold and drafts, but the way my house leaks heat you'd think the Gas Company built it."

"In the summer," Hart said, "there is a similar energy loss as heat enters homes that we use energy to cool."

I said, "Mr. Mart, I was puzzled by Grubisich's story because after it reported on how much energy your houses save, it indicated that other builders show little enthusiasm for your ideas. It quoted an official of the Northern Virginia Builders Association as saying, 'It's great if it works.' What is that supposed to mean?"

"It means," Hart replied, "that I don't think I'll be joining the Northern Virginia Builders Association."

Our story also quoted the NVBA man as saying that his organization had at one time thought about constructing an experimental house, but had dropped the idea to await the outcome of a similar project undertaken by the National Association of Home Builders Research Foundation. The implication was that data from the Research Foundation's experimental house was not yet available, but I decided to check it out anyhow.

When I called the NAHB on Monday afternoon, I was surprised to hear that Grubisich's story had not yet come to anybody's attention. Yes, an official confirmed, the Research Foundation, a subsidiary of NAHB, had indeed built an experimental house about a year ago, but the official knew very little about how the experiment was working out. He said Ralph J. Johnson, the foundation's president, might tell me about it.

It wasn't until I began talking to Johnson that I realized what the troublesome undertone in Grubisich's story had been.

Other builders may not have been excited about the concept of an energy-efficient house, but here at last was a man who really was.

"I've been an energy conservation freak since around 1955," Johnson told me. "HUD gave us a grant that made this project possible, and by the time we report back to HUD this summer, I think we're going to have a good deal of new knowledge to pass along."

HUD's money was used to build two outwardly similar houses in Mount Airy, Md., which is up on Route 40, beyond Damascus. One is a conventional house, the other has "thermal protection." If you ask whether that means insulatation, Johnson replies, "It means about 75 things -- no one of which is dominant. We're into a whole new concept of home design."

Both houses are leased to young couples with two school-age children. The energy used to heat and cool the two houses and operate their appliances is carefully monitored. Then the data is analyzed. One statistic hits the inquirer right in the eye: During the early winter months of 1978, the experimental house used 72.4 percent less energy than the conventional house!

If the Northern Virginia Builders Association had been interested in obtaining this information, it would have been as readily available to the association as it was to me.

Association officials might have reflected upon the fact that the energy saving was not an independent builder's claim, it was a finding produced by impartial scientists who are using a government grant to look for truth.

If the business-as-usual elements within the construction industry bestir themselves, home building could become a whole new ball game in the 1980s.