HVAC systems are mechanical, so they need to be maintained like all mechanical systems. 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 an annual tune up and maintenance process yourself, and save yourself some money.
First, take a look at your furnace. There should not be any combustion residue or black soot on or around the furnace. Next, turn up the thermostat so that your furnace turns on. Check to make sure the flames in the burner are blue and steady, not yellow or orange and flickering. Soot build-up or yellow flames are an indication of poor combustion, and if you are seeing any signs of either, call a professional technician to fix the problem.
Turn your thermostat back down and let your furnace cool. For extra safety, turn off the circuit breaker that powers your furnace. When the furnace is cool, remove the sides of your furnace. Use a vacuum with a long nozzle to get rid of any dust that may have accumulated. Then, use a damp rag to clean the blades of the blower fan and any other areas the vacuum could not reach. While you have the sides off, check to make sure your blower fan has oil cups at the ends of the central shaft (some are sealed shafts and don’t need oiling). If there are cups there, give them a few drops of oil.
If your blower has a fan belt, check its condition and tension. An electric motor and a fan belt drive many blower fans, while some are direct drive and don’t use a fan belt. Over time, fan belts age and heat will dry out the rubber belt causing cracks. Check to make sure the underside of the belt is free of cracks. If there are cracks, make sure to 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 at least a 1/2 inch of play in a properly adjusted belt. If there is more or less movement, 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, make sure to change your furnace filter once a month during heating season. This is good maintenance practice. So when you do your furnace tune up, get ready for the season by installing a fresh filter.