No furnace will continue to operate efficiently without periodic maintenance. Keeping the home's heating system clean, lubricated, properly adjusted, and replacing the filter regularly will not only result in more efficient heating, but will also extend the life of the system and save energy and expense.

Ideally, the furnace should be inspected and serviced by a professional heating contractor or qualified technician at least once a year, preferably before each heating season begins. Many heating companies offer such a service at a reasonable price. If you do your own maintenance, a qualified professional should examine the system every three to five years.

The first step in furnace maintenance is to replace the dirty furnace filter with a clean one. The purpose of the filter on a forced-air furnace is to keep dust, soot, and other contaminants out of the air that is blown into your living area. Once the filter has been sufficiently coated with this grime, it causes the furnace blower to work harder, making it more costly to operate and shortening its life span.

Since filter size and location vary from furnace to furnace, you'll need to check the owner’s handbook. If an owners handbook doesn't exist, this information usually can be found on the furnace or on an inside panel of the furnace. Some furnaces have more than one filter that will need replacement one near the blower and one at each cold air return. Buying replacement filters by the case will cut down on the unit price and will make replacement convenient.

Note: Here’s a trick that will help you decide on a good quality filter. If you can pour salt through the filter it’s no good. If it can’t hold salt it certainly won’t filter particles of dust and pollen.

The blower compartment of forced-air furnaces should be clean and dust-free. Use a vacuum with a dust brush attachment to remove any lint, dust, or debris that may exist. The same should be done for the fire box or burner compartment. Caution: Make sure that the furnace is turned off and has had a chance to cool completely before attempting to clean it.

There is nothing more disturbing than a furnace that sounds like an automobile skidding out of control each time the blower engages. If such is the case in your home, chances are that the fan belt needs to be replaced or adjusted. The fan belt should typically "give" only about 1/2 inch. In most cases moving the motor bracket will usually be all that's required.

Any other squeaks and creaks can be silenced with a little lubrication. All bearings and other moving parts should be lubricated with fine machine oil. If the furnace is oil-fired, the bearings in the pump motor should also be oiled periodically. The fuel filter in the main oil line should be replaced once a year. Finally, the burners should be adjusted to ensure that they mix the proper amount of fuel and air for safe and efficient combustion. This is something that most utility companies will do free as a service for their customers.