How to Clean an Air Conditioner Filter

Usually overlooked, air conditioner filters are responsible for an important job: filtering out dust, dirt, and other debris particles from the air we breathe inside our homes. They improve your air quality, but clean filters are also crucial to the internal workings of your cooling system. A dirty filter causes the aircon to work harder to push air through its clogged fibers, using more energy and shortening its lifespan. Often, you can avoid high energy bills and mechanical problems by keeping the air conditioner filter clean. 

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How To Clean AC Filter

Some air conditioner filters can be easily removed and washed, whereas others are made of paper or cardboard and are disposable and have to be replaced. Please refer to the manufacturer’s instructions to confirm the best technique for your specific filter type. 

Step 1: Find the filter location

Replacing an AC air filter is a quick and straightforward task, but before you can begin, you need to know where to locate the air conditioner filter. That can be tricky because there are several places it could be.

  • Window/Through-the-Wall Air Conditioners: On window and TTW units, the air filter is located right under the front inside the intake grill of the air conditioner. 

  • Portable Air Conditioners: Portable air conditioner filters are commonly found in a rear or side panel and are easy to locate. 

  • Ductless Mini-Split: Each indoor unit will have its own air filter. You can usually access it by opening up the front panel and removing the filter(s). Most ductless systems have washable/reusable filters.

  • Central Air Conditioners: The air filter is next to your furnace or AC system's air handler. The air handler is a large metal box that holds the fan and fan motor. Generally, the air handler is in a basement, an attic, or sometimes in the back of a closet. Depending on the type of unit and ducting, you may also have filters behind your return vents throughout your home.

Check your owner's manual for assistance if you have trouble finding where the filter is in your air conditioner. If you don't have the manual handy, you can look online for information from the manufacturer of your AC unit. 

Step 2: Turn off your AC unit

Now that you know where to find your AC filter and how to access it, the next step is to turn the air conditioner off if it isn't already. Turning off your AC will prevent any unclean air from circulating through the system and your home. Unscrew the vent cover or use the release handle to remove the filter when it's safe to continue. Gently slide the filter out and then give it a thorough inspection.

Step 3: Clean/Replace Filter

It is most likely that your AC filter will be clad with thick, grey dust and needs a thorough cleaning —or replacement.

If your air conditioner utilizes a reusable filter (one with a plastic or metal frame) – 

First, use a handheld vacuum cleaner or a bristled attachment with the telescoping arm of a carpet vacuum. Vacuuming will help you gently get rid of the dust and debris without making too much mess. 

Next, read the manual to see if your filter is washable. Some air conditioner filters aren’t meant to get wet, and you want to avoid causing damage. If your filter is water-friendly, soak it in equal parts water and vinegar for about an hour. Let the filter soak in the cleaning mixture for about an hour, then gently rinse thoroughly with fresh water.

If you do not have a basin, tub, bin, or container big enough to immerse your filter in with water, use a hose to wash it off. Ensure the hose pressure is low so that the filter does not tear. 

If your air conditioner uses disposable filters (which are often framed in cardboard) – 

Many disposable AC filters should be replaced instead of cleaning, as water cleaning can lead to possible mold issues. Check the size marked on the filter’s side to avoid purchasing one that doesn’t fit. Then skip to Step 5.

Step 4: Allow Filter to Dry

After washing your reusable filter, let it dry thoroughly. Reference the manufacturer's manual for any special steps you might need to take, but leaning it against something for a few hours while letting it air dry and flipping it over midway should do the trick.

Step 5: Reinstall Filter

Even reusable air conditioner filters can become worn or damaged over time and need to be replaced. Check the filter for any indications of damage – holes, excessive grim, or rips. If it's in working condition or you're using a replacement, you can place it back in the unit. Most filters have an arrow showing which way they're supposed to face. This arrow needs to point in the direction of the airflow. Close the panel or screw the vent covers back on, and you are finished! 

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Why Should You Clean Your AC Filter?

Without routine maintenance, the AC filter in your unit becomes less effective. Dirty filters often need more energy to run, increasing energy bills. If your air filter isn’t cleaned frequently, it can collect dust, grime, bacteria, mildew, and mold over time. These contaminants can enter your home and compromise the overall air quality. 

Changing the filter is vital for regular maintenance of your air conditioning unit, whether you choose a disposable or reusable air filter. 

  • Improved air quality: Since air conditioners filter pollen, allergens, dust, and other contaminants, it improves air quality in your home, providing comfort for allergy sufferers while making it easier to breathe.
  • Lower energy costs: Clogged filters make the air conditioner unit work harder. The harder the system works, the less efficient it is. The less efficient it is, the more it costs to operate and the higher the energy bill.
  • Longer lifespan: How long an HVAC system lasts depends on several factors. The lifespan of your air conditioner is linked to its efficiency. The harder the unit works, the quicker it can be damaged or overheated.

How Often Should You Clean an Air Conditioner Filter?

As a general rule, air conditioner air filters should be changed every 30-90 days to keep your system running smoothly and maintain optimal air quality. How often you change the air filter depends on various factors such as the number of pets in a household, size of your home, occupancy, time of year, air quality, and the filter type.

The only way to be sure about how often to change your air filter is to inspect the filter every month visually. After a few times, you'll get an idea of how quickly it becomes dirty. You'll need to reassess if you add a new pet to the family or if someone begins to show signs of allergies. When in doubt, purchase a replacement air filter and change it out.

Pro Tip: To check an air filter, hold it up to the light. If the light doesn't pass through the filter, it's dirty and needs to be changed. 


One of the most important things you can do on your own to take good care of your HVAC system is simply changing your air filter regularly. Replacing the air conditioner filter keeps your indoor air quality clean and your unit operating at its maximum efficiency. It's also a chore that many homeowners forget about for months, sending your energy bill skyward and potentially contributing to future maintenance issues.

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