SUPPOSE YOU could pick up the phone and call a house doctor. He would inspect your house, determine where energy was being lost and, on the spot, make minor modifications that would yield an immediate fuel savings of 20 percent. He would also suggest other changes that would produce additional savings of at least 30 percent. The total cost would be about $135, but smaller utility bills would soon pay this back and more. Would you make the telephone call?

Suppose further that after the house doctor's visit you could call a certified energy contractor. He would make the additional changes suggested in the earlier visit. Sometime after these changes had been made, your house doctor would return to ascertain that your house was actually consuming at least 50 percent less energy than before, and if it wasn't, to determine why not. The total cost for this second phase would be about $1,500, which would be paid by the utility and repaid by you if and when the house was sold. Would you take this second step?

Suppose, finally, that you were running the country and were told by your advisers that the nation's homes and commercial buildings concealed a rich supply of energy that could be "mined" for an equivalent cost of about $20 per barrel of oil. Your experts tell you that by recovering the energy now being wasted just in heating homes and businesses, the equivalent of 2.5 million barrels of oil per day could be saved by the mid to late 1980s, with some savings beginning within one year. With equivalent standards for new buildings and minor improvements in hot water heating, the savings would rise to well over 4 million barrels per day -- half the country's current imports and more than 10 percent of total energy use. The cost would not be insignificant, but you realize that consumers are already paying $35 per barrel for home heating oil and that energy prices will continue to rise. Also, you know that the cost is much less than the predicted cost of new supplies, such as synthetic fuels and unconventional gas. Would you order that this program be begun?

You won't find a listing for house doctors in your telephone book, but sooner or later you could. In the community of Twin Rivers, N.J., a team from Princeton University found that for less than $1,300 per home, energy use could be cut by at least two thirds -- even though the 3,000 homes they studied were already well insulated by common standards. What the Princeton workers and others in the field are discovering is that we know very little about the "thermal behavior" of buildings, and that most energy is being lost through previously unrecognized paths. Adding more ceiling insulation is not the answer. Such steps as plugging air flows to the attic from living area and basement and insulating the basement and base of the building are what yield the astonishing results that have been found.

If there is to be a house doctors program, three separate efforts will be required: 1) pilot projects in buildings across the country to discover heat-loss patterns by building type, and at the same time to test the effectiveness of each type of improvement in each type of building; 2) the training and certification of house doctors and energy contractors, and 3) the formulation of rules under which utilities could finance these investments in energy conservation.

The "production" of energy from buildings looks so attractive that it's hard to believe such an aggressive program isn't already under way.