Fall | Home Maintenance | HVAC

Save a Repair Bill this Fall With This 13 Step Furnace Maintenance Guide!

So here we are again, just a few weeks away from the first snowfall. Most of us have already begun our winter prep, stowing the patio furniture, pool toys, and lawn ornaments – saving them from the imminent winter conditions. And while it’s important to get the outside of your home squared away, it’s perhaps even more important that the inside of your home, particularly your furnace, is up to the task.

Sure, you can call an HVAC contractor to come by and evaluate the condition of your furnace, by why not save yourself a few bucks and do a bit of the maintenance work yourself?

Important: Before you do anything, make sure you turn off your furnace’s power and fuel supply.

  1. Remove the combustion chamber door. This is a simple enough task. The door is generally held in place by two screws. Once you’ve removed them, simply lift it up and pull it off. Be wary of unfiled edges on the door. If possible, wear gloves to avoid scratching or cutting yourself while working on your furnace.
  2. Inspect the burner flames. To do this, you’ll need to turn on the power switch and activate the burners by increasing the temperature on your thermostat. If the flames are blue, you’re in good shape. If the flames are yellow, it’s an indication that the burners need to be cleaned.

Note: there are two things to avoid when inspecting the flames. The first is to avoid breathing on the flame. The extra oxygen will turn the flame yellow. To avoid getting burned, do not adjust the burners yourself; if you need to, call in a professional.

  1. Vacuum out the burner and blower cavities. Turn off the gas and power to your furnace. Start by vacuuming the burners themselves, and then move to the base of the furnace. In order to reach the back of the burners, tape a 20-inch length of drain line hose to the end of your vacuum. Not only will this help you reach the back of this cavity, it will also prevent you from accidentally damaging one of your furnace’s components as you vacuum.

Remove as much dust as you can. Keep an eye out for black soot – this might be an indication of poor combustion.

  1. Remove the blower and clean it. If there’s a panel in front of the blower, use a screwdriver to unfasten it (it’s okay to let it hang, but do so gently so as not to put any strain on the wiring). You’ll then need a 7/16 socket and ratchet to remove the bolts that hold the blower in place. Once that’s done, remove the blower – but do so gently. The blower contains some of your furnaces more vulnerable components.
  2. Vacuum and brush the blower blades. Before you attempt to clean the blower blades, make sure that you’ll be able to clean all of them. If you can’t, there’s a chance you could throw the blower off balance. Using a small brush and your vacuum, diligently clean each blade taking special care not to disturb the counterweights located on each blade.
  3. Change the furnace filter. Place a new air filter next to the blower. If you decide to purchase a high efficiency filter, be sure to consult your user manual beforehand. Some of the high-efficiency filters can actually restrict airflow, put strain on your blower, and reduce your furnace’s efficiency.
  4. Blow dust off the pilot. Using a plastic straw, blow off any dust that’s accumulated on the pilot. If your pilot is dirty, your furnace’s flame sensor might get a false reading that the pilot isn’t lit.
  5. Clean the flame sensor. Over time, your furnace’s flame sensor will become covered with residue that could prevent your furnace from lighting. You can remove the sensor by pulling it out of its bracket then, using a soft cloth, wipe the sensor clean before returning it to its bracket.
  6. Dust the hot surface igniter (without touching it). Like you did in step 7, use a straw and blow air directly on the igniter to remove any dust that’s accumulated. This is the only way you should attempt to dust the igniter. In addition to it being very hot, the igniter is also very fragile, so touching it while cleaning is never recommended.
  7. Inspect the drive belt. Examine the drive belt. If you notice that they’re any cracks or fraying, it’s time to replace it (this’ll generally cost you about $5 from your local hardware store). If you have to replace it, use a wrench to adjust the tension so it deflects between 1/2 and 3/4 inches.
  8. Lubricate bearings (if necessary). If you furnace is a little older, it’ll likely have two motor bearings and two blower shafts that you’ll need to lubricate on an annual basis. If needed, remove the caps and add two or three drops (no more) of lightweight machine oil. Replace the caps when finished.
  9. Adjust dampers (if necessary). If your heating ducts also serve as air conditioning ducts, they’ll likely have dampers that you’ll have to adjust from one season to the next. These settings should be marked. Adjust the damper to winter, which will direct more warm air downstairs.
  10. Seal leaky air ducts. If you have any leaky ducts, you can seal them using metal tape or a tube of high temperature silicone. Adjust your thermostat so that your burners turn on. Hold a lit stick of incense next to the draft hood; if its properly sealed, the smoke will be drawn to the hood.


Now that you’ve finished inspecting your furnace, remove and vacuum any floor registers you have throughout your house to remove dust, pet hair, etc. This will increase the efficiency of your heating system, and help you breathe air that’s a little cleaner this winter.

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One Comment

  1. I do think it is important to have your furnace looked at and cleaned each year as it can help you identify any issues sooner rather than later. I typically don’t recommend people to do this on their own, and I probably wouldn’t myself – as servicemen have a trained eye and are more experience. Great tips and information for those who want to try it. Thanks for sharing!

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