How to Clean a Furnace Filter

Co-authored by wikiHow Staff

Last Updated: March 30, 2023

If you have a home with a furnace, your filter will need periodic cleaning to remove dirt, dust, and other debris. Make sure your filter is reusable. Reusable filters should be labeled as such and are usually made of plastic-like materials. If your filter is not reusable, replaceable/disposable filters are available to purchase online or at hardware stores. To clean a reusable filter, remove the filter carefully, run it under water, and set it out to dry. When you're done, your filter should be clean and can be reinstalled.

Part 1

Part 1 of 3:

Removing the Filter

1
Turn off the furnace. Never remove a furnace filter while the furnace is running. Make sure to switch the furnace off before you begin.There is usually a handle somewhere near the furnace that can be switched off.^{[1]
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- If you're unsure how to turn off your furnace, contact your landlord or the manufacturer.
2
Locate the filter. Inside the furnace, you should see a filter. Usually, the filter is either just inside the furnace or just inside the air vent. The filter should have an arrow on it indicating airflow direction.^{[2]
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3
Mark the direction of air flow. Before you remove the filter, take a sharpie. Draw an arrow pointing in the direction of airflow somewhere on or near the furnace. This way, you will reinsert the filter in the right direction.^{[3]
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4
Remove the filter. Once you've located the filter, you can remove it. You should not need any special tools. Simply grab the filter with your fingers and slide it out of place.^{[4]
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Part 2

Part 2 of 3:

Cleaning the Filter

1
Make sure the filter is reusable. If your filter has a plastic frame, it's a reusable model. You can clean it out and place it back in your furnace.^{[5]
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Go to source} Disposable filters tend to have cardboard frames. For disposable filters, discard the old filters. You will have to get the same type of filter at a hardware store to replace the old one.^{[6]
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- Make sure to note the type and size of filter if yours is not reusable. You will need to purchase the same type/size to replace it.
2
Rinse away the dust with water. Filter cleaning is actually very simple. No special cleaners are required. You simply rinse your filter under running water water to remove any dirt, dust, or debris caught in the filter. When necessary, turn the filter around to get all the sides clean.^{[7]
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3
Let the filter dry completely. Set the filter somewhere to dry once you've cleaned it. It's best to let the filter air dry. Drying times will vary depending on the temperature of your home, but make sure the filter is completely dry before reinserting it in the furnace.^{[8]
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4
Put the filter back in place. Again, no special equipment is required to reinsert the filter. You simply need to slide it back in place.^{[9]
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- Make sure to pay attention to the arrow you drew. Place the filter in the right direction of airflow.

Part 3

Part 3 of 3:

Caring for the Filter

1
Figure out how often your furnace filter needs cleaning or replacing. Different types of furnace filters should be cleaned more or less often. Check your filter's label to see what type it is and clean it accordingly.^{[10]
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- Electrostatic filters need to be cleaned every three months.
- Electronic filters should be cleaned weekly.
- Mechanical filters are not reusable and should be replaced once a month.
2
Keep records of when you cleaned your filter. Each time you clean your filter, make a note of it. Write it down on a physical calendar or one in your home. Make a note of when the filter needs to be changed next. This will help you stay proactive about cleaning your furnace filter.^{[11]
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3
Replace your filter regularly. Even reusable filters have a shelf life. Check your filter's label or read your furnace's instructions manual. This will tell you how long your filter will last. Electromagnetic filters, however, do not need replacing unless they are severely damaged.^{[12]
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