Having made the nation's auto manufacturers develop more fuel-efficient cars, the federal government is now attempting to force home appliance makers to come up with more energy-efficient air conditioners, freezers, stoves and the like.

Authorized by laws Congress passed in 1975 and 1978, it's a one-two-punch by the Federal Trade Commission and the Department of Energy. As with autos, the government, first through the FTC, will require efficiency labeling.

But the program will not be limited to voluntary disclosure. The D.O.E. is in the process of setting minimum energy-efficiency standards most appliances will have to meet to be sold in interstate commerce.

Last November the FTC put out rules requiring certain appliances to carry labels with energy-efficiency and cost information. The same data required to be carried in catalogues advertising those appliances, including refrigerators and freezers, dishwashers, water heaters, clothes washers, room air conditioners and furnaces. With their usual desire for uniformity, the agency established the color of the lables -- yellow -- and even the typeface to be used -- helvetica.

After study, the commission decided that clothes dryers, kitchen ranges and ovens and television sets should be exempted because, according to the Aug. 11 Federal Register (page 53340), "labeling of these products would not be economically feasible," since among the information needed was how much a consumer was likely to use it in a year.

A key part of the commission rule was that the data used to make up the label had to be based on a standardized test, which the DOE was responsible for developing as part of its reasonibility in setting standards.

Now the FTC is about to add to its labeling list central air conditioners. It had been delayed because the DOE had trouble coming up with a test and the FTC didn't quite know how to determine an annual energy cost, since use varied from place to place.

DOE worked out its tests, and the commission developed a map with the United States divided into six regions based on estimated "cooling hours of use." Washington, D.C., for example, is in region IV, with an average of 800 hours of use, according to the map. Under the FTC proposal, each air conditioner purchaser would be given a map and other data so he may calculate the annual cost of operating that particular central air conditioner.

While the FTC labeling program in in its final stage, DOE, according to the Aug. 12 Federal Register (page 53488), has decided to extend public comment on its proposed energy-efficient standards for several appliances -- refrigerators, freezers, clothes dryers, water heaters, room and central air conditioners and kitchen ranges and ovens.

The public will have until Sept. 15 to send in its views, because officials said some manufacturers who fear their products may be barred by the limits have asked for more time to gather data.