Best Way to Clean My Furnace


Best Way to Clean My Furnace


Many people are intimidated by their furnace and air conditioner, but it is merely just another piece of equipment that needs some TLC from time to time. While you may need to call in an expert if your unit is NOT operating properly, regular maintenance is something that most homeowners can handle on their own. I have found, what I believe, is the Best Way to Clean My Furnace.

Although each make and model is somewhat different, there are some simple Steps that are somewhat universal for maintaining most furnaces.


Materials & Supplies Needed:

  • Replacement Furnace Filter

Purchase Furnace Filters at:


Tools & Supplies Needed:

  • Safety Glasses
  • Mechanics Work Gloves
  • Shop Vac (or Standard Vacuum) with Crevice Tool Attachment
  • 1/4” Drive Ratchet, Short Extension, Various Sockets
  • Mini Wire Brush

Purchase Tools & Supplies Needed at:





Step-by-Step Instructions


Step 1 – Create a Materials & Supplies Needed Sheet

Before you can complete the first (4) Steps in this project, you will need to know your furnace filter size in order to obtain the correct replacement. You can either consult your furnace maintenance manual if it is handy, or you will need to remove the old filter and check the size, which should be clearly marked on the filter.

To remove the old filter, complete as follows:

  • Turn OFF the blower switch next to your furnace (if you have one) or turn off the circuit breaker (or remove the fuse) for the furnace. Next, take the front panel OFF of the furnace.
  • Lift up the front cover slightly and pull it toward you to remove.
  • Remove the lower panel by gripping the sides and pulling it toward you.
  • Lift up any spring holder holding the filter in place, and slide the old filter out.
  • Inspect the cardboard sides for size Information and write down dimensions on a piece of paper.

If you have a reusable, cleanable, foam filter, the instructions for cleaning will be found in Step 5.


The Information to complete the first (4) Steps is found in the Page:    Steps Common to All Projects

Simply click on that Link and you will be directed there.

You can also access it in the drop-down Top Menu under:   Home

After completing these (4) Steps, simply click on your ‘back arrow’ (top left corner of the page) to return to these instructions and begin with Step 5.

Purchase Furnace Filters at:


Step 2 – Calculate Project Cost

Step 3 – Order Your Materials & Tools Needed

Step 4 – Inspect Your Delivery

Step 5 – Clean Reusable Furnace Filter

If you have a reusable, cleanable furnace filter, take the filter out, clean it, dry it, and reinstall.

Once your reusable filter has been removed, take your shop vac and vacuum the entire surface, removing any dust. Then, if your filter has a separate foam covering, remove it and rinse it thoroughly under warm water, occasionally squeezing it out to remove all dust. Once the squeezed water runs clear, place the foam covering in an appropriate place to allow it to fully dry before replacing it. This may require you to have to flip it over once the first surface area is dry. Once dry, replace it onto your filter, and reinstall the filter.

If your filter is the disposable type, simply replace it with a new one after completing Step 6.

Purchase Shop Vac at:



Step 6 – Vacuum the Furnace Cold Air Return

With your filter removed, take your shop vac (or standard vacuum cleaner) with the crevice tool attachment in place, and vacuum the cold air supply grate, inside and out. This is the grate that is located closest to your filter. When you are finished, replace your filter.

You should also vacuum all cold air return grates which are on every floor of your home. These are usually located at the end of hallways.


Step 7 – Vacuum the Furnace

Vacuum all the rest of the furnace, beginning from the top and working your way down to the bottom. Be careful NOT to disturb any wire connections. Vacuum all parts that contain dust, including:  furnace walls, burners, wires, blower motor ends, floor, etc.


Step 8 – Clean the Blower Motor Squirrel Cage Fan

Remove the blower motor and clean the squirrel cage fan.

Most furnaces have a ‘squirrel cage’ fan attached to the blower motor. This type of fan provides quieter and more efficient air flow. It is a circular fan with multiple fins which can become caked with dust over time. These fins should be cleaned every 2 – 3 years, or more often in a very dusty or pet environments.

Before removing the blower motor, you will need to first make sure that all power is OFF to the furnace, as was instructed in Step 1. Then, either take a picture with your smart phone of the blower motor wires or mark down on a piece of paper indicating the wire colors and their positions. These are the wires coming from your blower motor and running to a junction box. They are usually just clipped in place. These wires will need to be removed before removing the blower motor. The picture or the marking down of the colored wire positions will insure that they are able to be replaced correctly when cleaning has been completed.

Once you have recorded the blower motor wire positions, disconnect the wires. Be very careful NOT to touch the terminals on the capacitor, which is usually attached to the motor housing cover, or you may get quite a little electrical jolt. Now we will unbolt the motor.

Usually, there are only (2) small bolts holding the blower motor in place. These will be located near the front of the motor on either end, attaching the motor frame to the furnace. Using your 1/4” ratchet, small extension (if needed), and correct socket size, remove the (2) bolts and set them off to the side.

Once the wires and the bolts have been removed, the blower motor should just slide out toward you. Be careful, as these motors tend to be rather heavy. Once removed, set the motor down on the floor, and using your small wire brush, clean all of the motor fins. Then, take your shop vac and vacuum up any dust. You can also take a damp rag, and wipe each of the fins when you are finished removing all of the heavy dust and dirt.

Next, vacuum both ends of the motor, including any wire coils that are there. Then, check to see if your motor contains any oiling ports. These ports will be located at either end of the motor, allowing a few drops of oil to be added to keep the motor bearings lubricated. It will usually be a small plug, or possibly a small hinged pop-up door. Older motors will have these. Newer motors will NOT have these, as they usually have sealed self-oiling bearings.

If you do have the oil ports, remove the plugs, and place 3 – 4 drops of lightweight oil in each port. Use either a 10W motor oil, machine oil, or sewing machine oil. Do NOT put more than the recommended amount of oil into each port, or you may damage the motor.

Once the motor has been cleaned and oiled, you should reinstall the blower motor, reversing the removal process. First, slide it back into place, screw in your bolts and tighten snug, but do NOT over tighten and strip out the bolts. Then, reattach your wires according to the color coded positions that you previously recorded.


Step 9 – Replace Your Furnace Doors and Test

Once all of the cleaning has been completed, replace both your lower and upper furnace doors, turn the power back on, and test your furnace by turning up the heat on your thermostat.

If you are unsure about the cleaning of your furnace, you can always hire a professional to come and do the work for you. You can find reputable Contractors & Handypersons at any of the following:



Nice Job! Your Furnace should give you another Year of Good Service!


Please take the time to leave a Comment, letting me know how your project went.



CJ Dodaro

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