Annual Furnace Tune-up and Maintenance

A gas furnace tucked away in a back room of the house.

We've all felt the pinch of rising home heating bills. In 2010, the average cost of heating a home for an American family was about $1000, so anything you can do to reduce that number is obviously well worth the effort. One thing that can help minimize your heating costs is giving your furnace a tune-up to ensure it is working efficiently.

A Typical Home Heating (HVAC) System

Home heating systems basically consist of three parts. A heat sensor, or thermostat, measures the temperature in your home and determines when it needs to be raised. When the air temperature drops, the thermostat signals the heater and the blower to turn on. The combustion in the heater creates heat, while the blower moves air over the heat exchanger, raising its temperature and distributing it throughout the house via heating ducts. Cooler room air is returned to the furnace through return ducts where it is warmed. The warm-air-out, cool-air-in cycle continues until the desired temperature is reached and the thermostat signals the furnace to shut down.

Tune-up a Furnace System

HVAC systems are mechanical, so like all mechanical systems, they do need to be maintained. A thorough professional tune-up will cost you $100 or more and is definitely something you should do every few years. However, you can do annual maintenance yourself and save some of that money.


First take a look at your furnace. There shouldn't be any black soot or combustion residue on or around it. Next, turn up the thermostat so your furnace comes on and check the flames in the burner. They should be blue and steady, not yellow or orange and flickering. Soot build-up or yellow flames are an indication of poor combustion, so if you see any signs of either, call a professional technician to fix the problem.


Next, turn the thermostat back down and let your furnace cool. For extra safety, turn off the circuit breaker that provides power to your furnace. When the furnace is finally cool, remove the sides and use a vacuum with a long nozzle to get rid of any dust that may have accumulated. Use a damp rag to clean the blades of the blower fan and any other areas the vacuum can't reach. While you've got the sides off, check to see if your blower fan has oil cups at the ends of the central shaft (some pricier furnaces are sealed units and don't need oiling). If there are cups there, give them a few drops of oil.


An electric motor and a fan belt drive many blower fans, while some are direct drive and don't use a fan belt. If your blower does have a fan belt, check its condition and tension. The underside should be free of cracks, but over time, age and heat will dry out the rubber belt and cause cracks. If there are cracks in the belt, replace it with one of the same size.

Checking the tension of the belt is as simple as pushing down on it. There should be about half an inch of play in a properly adjusted belt. If you have more or less movement than that, adjust the tension by loosening the electric motor mounts and moving the motor to create the proper tension.


Reattach the furnace panels, and turn the circuit breaker back on.


Finally, changing your furnace filter once a month during heating season is a good maintenance practice. So when you're doing your furnace tune-up, get ready for the season by installing a fresh filter.

Now your furnace is ready for "Old Man Winter."

Stay Safe

Combustion creates carbon monoxide (CO), a colorless, odorless gas that can be deadly. Normally the CO produced by the combustion in your furnace is exhausted up the chimney and out of your home. However, a furnace that is out of adjustment can leave CO in your home. You can help protect yourself from CO poisoning by installing a carbon monoxide detector in your furnace room. If the detector indicates any buildup of carbon monoxide at any time, shut the furnace down and have it professionally inspected immediately.

While doing your own tune-up will help keep your furnace running efficiently, a professional inspection and tune-up every few years is still a good investment. The pros are the people who have the skills and equipment to ensure that any parts that might degrade over time are still functioning properly.