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Furnace Maintenance: Cleaning Your Furnace

When it comes to maintaining your furnace, keeping it clean can go a long way. Dirt can build up on the internal components of the furnace and cause it to not work as efficiently as it could or stop working altogether. If you are up to the task, here are a few things you should clean at least twice a year.

If you aren’t comfortable poking around inside your furnace, don’t do it. All of this and a whole lot more should be done with the annual dealer maintenance when you have your furnace serviced each year.

1. MAKE SURE FURNACE IS WORKING

Before you do anything to your system, you want to make sure it is working. That way you know, when you turn it back on and it doesn’t work, you can retrace your steps and see if you accidentally did something to cause the issue.

Go to the thermostat, turn it to heat mode

Turn the temperature up high enough so the furnace comes on

A person presses the middle button on a wall-mounted Alarm.com security system control panel.

2. CLEAN AROUND THE FURNACE

It’s a good idea to keep the area around the furnace clean as well as the furnace itself clean. We made a video that goes over Getting Your Furnace Ready For Winter if you’d like to reference that.

  • Move boxes and other clutter from around the furnace
  • Vacuum the area around the furnace
  • Wipe down the outside of the furnace
A vacuum cleaner hose is being used to clean debris from underneath a gray furnace with a warning label attached.

3. SHUT THE POWER OFF

When working on the actual furnace unit, you want to find the switch on the furnace that shuts the power off.

A hand is flipping a switch on an electrical outlet, which also has a black power cord plugged into it.

4. CHANGE YOUR AIR FILTER

A dirty filter restricts the airflow and when your furnace can’t move enough air to disperse the heat it’s creating, it can overheat. This can make you think your furnace isn’t working but in reality, it’s just a dirty filter.

  • Remove your old filter
  • Install the new one being careful to make sure you install it with the airflow arrow pointing in the right direction
A person replaces an air filter in a furnace, holding the filter in front of the open compartment.

5. VACUUM & DUST INSIDE

You will need a vacuum, some compressed air, and a soft-bristle brush for this next part. Be gentle when you are cleaning the inside of your furnace, especially around the circuit board.

  • Remove the doors of your furnace to expose the inside
  • Vacuum the inside of the unit where you can reach
  • Use the soft-bristle brush to gently dust the gas assembly and other components. Keep the vacuum going so that you get the dust that’s being stirred up
  • Use the compressed air on the circuit board and other tight spots
A person uses a vacuum cleaner nozzle to clean dust and debris inside an open furnace with visible wiring and components.

6. CHECK ELECTRICAL CONNECTIONS

You want to make sure that there aren’t any loose electrical connections. 

  • With a small screwdriver, turn to see if the connections are tight
  • Lightly tug on the wires to see if any of them are loose or come out
A hand adjusts multiple colored wires connected to terminals on a green circuit board labeled "EMERSON.

7. CLEAN BLOWER FAN

If the blower gets dirty, it can’t move as much air as it was designed to and can cause the fan to wobble, making noise and shortening the life of the fan. So, clean as good as you can with where you can reach. If your fan is really dirty you may want to have a professional clean it.

  • With the vacuum, vacuum the front and back of the blower fan and fan motor
  • Look for signs of oil dripping down
Close-up view of an electric motor with exposed colored wires and visible dust buildup on its surface.

8. TURN FURNACE BACK ON & LISTEN

At this point, I like to turn the furnace back on and if it fires up and stays on, I’m good to go. You want to listen to the ignition to make sure the gas ignites and stays lit.

  • Put the cover back on
  • Turn the power on 
  • Adjust thermostat if you need to so that the furnace kicks on
  • Listen for these 3 things: gas valve to open, gas to ignite, gas stays lit
A technician inspects a furnace. Inset shows the inside of the furnace. Text reads: "Gas comes on, flame ignites, flame stays on," with green check marks.

9. OTHER PARTS TO CLEAN

The things listed above are all most of you will need to do but if you wanted to go above and beyond you could also clean your flame sensor, the gas jets, and the blower wheel. Those are for future articles though.

A man points at a warning label on a gray Amana furnace unit in a basement.

We hope you found this information helpful. Let us know if you did. And if you need help with this or any other projects around the house, Any Hour Services has technicians that would be happy to help with any size project you’ve got.

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