Introduction: How to Do Seasonal Furnace Maintenance

While not everyone does it, it’s extremely important to perform furnace maintenance to ensure that it’s running effectively and safely. It’s actually not all that difficult—pretty much anyone can do it, and if you’re a homeowner, you should know how to do it.


• New air filter
• Light oil for motor bearing


• Screwdriver
• Vacuum (with long snorkel attachment)

Step 1: Turn Off Furnace Power

The first step is to turn off the gas and power that operates your furnace. There should be a switch located close to your furnace. If this is not the case, go to your electrical service panel and turn off the proper breaker. To turn off the gas, locate the gas line, which is connected to the furnace via a black pipe and turn it off by using the shut-off valve.

Step 2: Vacuum the Interior of Your Furnace

Next, you’ll need to open your furnace door. Using a vacuum equipped with a long snorkel attachment, clean out the gas burners and the base of the furnace. Be sure to get rid of any loose debris or dust.

Step 3: Change Your Furnace’s Air Filter

During the heating season, you’ll most likely need to change your furnace’s air filter monthly. The air filter will either be located between the return air duct and blower or in the blower door unit itself. You might have to use a screwdriver to pry open the blower door or access panel. Once this is done, remove the air filter. With fiberglass or paper filters, you’ll notice there is an arrow on the filter’s frame that shows how you should insert the filter. If you have a foam filter, simply wash or vacuum the filter in order to clean it, and then replace it as appropriate.

Step 4: Check Your Furnace’s Fanbelt

Fanbelts are known to get loose and wear down, so it’s important to check your furnace’s fanbelt as you’re doing seasonal maintenance. Inspect the belt for cracking, glazing, or fraying. If you see any of these, then replace your fanbelt. Also check your belt’s tension by pushing down in the center of it. If it feels taut, then it’s okay. If it deflects more than ¾”, then you’ll need to tighten your belt by loosening the attachment bracket and then moving the motor assembly in order to tighten the belt. Finally, tighten the attachment bracket once again.

Step 5: Lubricate Your Furnace’s Oil Bearings

If your furnace has a motor lacking permanently sealed bearings or if it’s an older furnace, the bearings will need to be lubricated. First, locate the oiling caps, which could be on the bearing shaft. Drip a few drops of household oil in the spout below the caps, and be sure not to over oil!

Step 6: Replace Furnace Cover and Turn on Gas and Power

After you’ve done the first five steps, it’s time to replace the furnace cover and turn the gas and electrical power back on. If necessary, relight the pilot.

Step 7: Know When to Ask Questions

There may be times when you are performing seasonal furnace maintenance when things are not going as planned or you have questions that you can't find the answer to online. In this case, call a friend or contact a local service provider who may be able to provide the guidance you need. The easiest way to do this is often to do a Google search for providers in your local area. For example if you live in Louisville, you might search for Louisville heating. You can always find this information in the Yellow Pages as well. Most importantly, try to find at least a couple of good reviews before contracting with a service professional.