September 11, 2020
By Mark Paup

The Best Way To Clean An AC Filter

Updated January 23, 2024

It may be a simple task, but too many homeowners forget to check their AC system’s air filter. While some air conditioners use permanent filters, disposable filters tend to be more common (and often more effective at trapping particles.) However, no matter what kind of filter your air conditioning system uses, one thing always holds: air filters must be regularly cleaned and/or replaced.

The reason it’s so important to have clean, well-functioning air filters comes down to cost and air quality. The more dust and debris your furnace traps in the air, the harder it will be for your system to effectively cool your house. And when your AC system has to work harder to cool your home, your energy bills will inevitably go up. Moreover, if your AC unit’s filter is extremely clogged with dust and other particles, your AC will spread those particles around your house, reducing the indoor air quality for everybody.

Keep reading to learn the best way to clean your air filter.

Avoid high energy costs and poor air quality with our expert HVAC techs at Golden Rule.

How to Clean Your AC Filter:

  1. Make Sure You Have the Right Tools:
    The good news when it comes to cleaning your AC filter is that it can usually be done with items that are just lying around your house. You may need to start with a screwdriver to remove your AC vent. You should also grab a handheld vacuum with an attachment and a hairdryer with a cool setting. Beyond that, some regular dish soap, a sponge, and water should be enough to get the job done. Of course, there is one final component that may be necessary for this process—a replacement filter. This is only going to be required in cases where your disposable filter is too dirty to clean. Attempt the filter cleaning process first and put it back in your system. If your AC unit still isn’t functioning well or is giving you a warning that your filter is dirty, try cleaning it one more time. If your system continues to have issues after the second cleaning, you’re going to want to just put in a new filter entirely.
  2. Find the Filter:
    Many air conditioning systems will give you a warning light, indicating when it’s time to change your air filter. For other units, you may not know your filter needs to be changed until you feel a decline in your indoor air quality. However, you won’t know the extent of the problem till you get your eyes on the filter in question. First, make sure your system is turned off (you don’t want unfiltered air circulating your space.) In the case of most AC units, the filter is located behind the return vent, usually by the ceiling or close to the floor. Some systems have multiple return vents, so if you’re checking one of them, make sure to check all of them. In the case of window units, the filter is usually located directly under the cover. If your AC’s cover is screwed in, take your screwdriver and remove it. Make sure to remove the filter carefully, so it is not damaged.
  3. Thoroughly Clean the Filter:
    Once the filter has been removed, examine it for dust and discoloration. If the filter looks excessively gray and worn out, you may need to replace it. Otherwise, you can start cleaning it using your handheld vacuum. Again, carefully handle the filter, removing the dust with the vacuum attachment gently. If your filter still looks dirty after that, run it under warm water, placing it facedown so the water passes through it and rinses out debris on the other side. For the final time, be careful. Scrubbing too hard can damage the filter.
  4. Dry the Filter:
    After you finish vacuuming and washing your filter, put it in a safe place where you can leave it to dry. You may need to consult the manufacturer’s instructions to see if your filter requires any special treatment, but in general, let it dry for two hours – flipping it halfway through – should do the trick. You can also dry it with a hairdryer on the “cool” setting. Drying your filter with air that is too warm may damage it, however, a hairdryer can be useful if it’s extremely hot out and you want to put your filter back in the AC unit ASAP.
  5. Put the Filter Back:
    Once your filter is completely dry, put it back in the unit, making sure it is inserted correctly and in the exact right place. After that, turn your AC back on again and check if it is working correctly. If you have a window unit, you may want to unplug the unit before turning it on again. If your system is still telling you the filter is dirty, try cleaning it again. And to reiterate, if your filter is still dirty after that, cut to the chase and replace it.

For more information on AC care or to schedule service, call 515-393-4526, or send us a message:

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If you found this post helpful, check out what happens if you don’t change your furnace filter:

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