Using no more power than a lightbulb, small doses of microwaves can warm people as effectively as furnaces that consume far more energy, a Harvard physics professor figures. There is no safety problem, contends Prof. Robert V. Pound in Science magazine, and such a development "could contribute importantly toward alleviating the developing world energy crisis." When a microwave generator is installed in a room, the waves will heat the people, not the air. Even when the air is chilly, the people will feel toasty, Pound believes. The only hitch, he says, is that the walls, floors and ceilings would have to be covered with metal foil in order for the microwave heating to be efficient. The foil, which he suggests could have a decorative facing, would reflect the microwaves and keep them in the room. Furniture would also have to be designed so that it would not absorb the waves and waste energy. Pound believes his scheme might eliminate the need for space heating altogether in some climates, while "in others, the heating of buildings might be reduced to a level sufficient only to avoid freezing and discomfort from contact with cold objects." Pound figures that in a room where the air temperature is 50 degrees, 60 watts' worth of microwaves would make one person feel as if the temperature were 72. Of course, if there were two people in the room, twice as many microwaves would be required. If not everyone in the room likes the same temperature, those who want to be cooler could wear clothes with metalized threads to screen out some of the waves. Pound says his plan is safe because the microwaves would be very short -- only one centimeter long. The waves in a microwave oven, by contrast, are 12 centimeters. The very short waves would penetrate only the skin, Pound says. "It seems likely that there is little difference between being warmed by such microwaves and being warmed by more conventional infrared waves," he says. "No great danger has been cited from the radiation from a fire on the grate or a stove."