It's a good time to tune up home heating systems for winter savings

Utility companies say that homeowners can save as much as 10 percent of their fuel cost by a regular program of heating-system maintenance. As a result, the system could be expected to run more efficiently, and use less fuel, than if it were not in tune.

The summer is the best time to put the heating system in shape. Thus, you could avoid a breakdown when you most need it.

With that in mind, here are a few ideas that can cut the heating bill:

* Check gas furnaces every two or three years; oil furnaces annually.

On a gas furnace, a service person should clean and adjust the thermostat contacts; check the main fuel valve, regulator, and safety valve; and adjust the air-supply nozzle. On oil furnaces, the fuel mixture and ignition system need to be adjusted and various filters changed.

* Compare the furnace thermostat readings with a portable thermostat to make sure the fixed readings are accurate.

* Change or clean the filters regularly in a forced-hot-air system.

* Vacuum the ducts and grilles occasionally to remove any dust buildup.

* Clean the fan blade annually - after you turn off the electricity to the furnace.

* Lubricate the furnace motor several times a year in hot-water systems.

* Bleed air from the radiator pipes (in steam or water systems) at the beginning and middle of the heating season. Then open the air-vent valves monthly at high points in the system.

Changing from one fuel to another can, in some cases, be an expensive mistake , so be sure to compare costs carefully. It doesn't mean a consumer should not get rid of an inefficient system for more modern equipment. If your home uses oil heat, contact a reputable dealer to investigate the efficiency of your present system and make recommendations for upgrading.

A Department of Energy study shows that fuel-bill savings can run up to 20 percent if the thermostat is turned down at night from 6 to 8 degrees, depending on the climate and insulation in the house.

Remember this next fall when you put the heating system back into action.

''Dialing down'' the thermostat during the day can be another way to cut fuel costs. There is no excuse for forgetfulness, because automatic timers can regulate the thermostat setting.

The little time and money you use now on these simple heating-system checks can reduce emergency calls during the winter and costly bills later on.