How to Clean an Air Filter

Plant next to an air filter

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There is little more vital to the good health of your family than having clean air to breathe, especially in your home. One essential way to improve the air quality in a house is to use air filters and keep them clean. The filters will trap dust, dander, and other polluting particulates that cause allergies and even permanent harm to respiratory systems.

Many homes have several appliances and systems that use air filters. The largest is a heating, ventilation, and air conditioning system (HVAC). Individual room heating and air systems, window air conditioners, air purifiers, humidifiers, dehumidifiers, range hoods, clothes dryers, and vacuums have air filters that should be cleaned or changed regularly.

How Often to Clean Air Filters

Air filters should be cleaned or replaced on a routine schedule. Most HVAC filters should be cleaned or changed every two to three months. More frequent cleaning is needed if you live in an area with lots of dust or in a home with lots of pet hair or if you don't clean regularly.

An easy way to tell if an air filter in any system or appliance needs cleaning is to remove it from its usual location. Hold the filter up to a bright light or window. If you can see light coming through, it can be used for a bit longer. If no light comes through, clean the filter or replace it.

Should You Clean or Replace Your Air Filter?

How do you know when replace the filter or completely replace the appliance? Some dirty air filters can be easily cleaned and returned to the appliance, others will not stand up to cleaning and must be replaced with a new filter. How do you decide?

Disposable filters are designed for one-time use and are less expensive than washable filters. The frame is usually made of cardboard that will not stand up to cleaning. Attempting to clean a disposable filter can cause matting of the fibers, encouraging mold and mildew to grow and reducing the effectiveness of the appliance. Washable filters have metal or plastic frames and are more environmentally-friendly, but take more effort to maintain.   

One way to determine what type of filter you have or can use is to consult the appliance manual. There you will find instructions on how to clean or replace the filters, as well as a suggested schedule for changing or replacing filters so the appliance maintains optimum performance. If you have lost the manual, consult the manufacturer's website, which will offer advice on cleaning and replacement filters.

What You Need

Supplies

  • Warm water
  • Liquid dishwashing soap

Tools

  • Vacuum
  • Water sprayer
  • Sponge or soft-bristled brush
  • Drying cloths
  • Stepladder
  • Screwdriver (optional)

How to Clean a Washable Air Filter

  1. Hit the Off Switch

    Before you begin the process of cleaning an air filter, make sure that the HVAC system or appliance is turned off. For small appliances, it is best to unplug the machine to avoid any potential for electrical shock. If you leave an HVAC system running during the time the filter is being cleaned or replaced, it will draw excess dust into the fan and motor.

  2. Open the Filter Cover

    Many filter covers have latches that can be opened to access the filter; however, some are attached with screws that you need to remove with a screwdriver. Be sure to put the screws in a safe place. If you are working on an overhead HVAC vent, use a sturdy stepladder.

  3. Head Outside

    If at all possible, take the filter outside to begin the cleaning process. Tap the filter lightly to remove loose dust. Use the brush attachment on a vacuum hose to thoroughly clean both sides of the filter.

  4. Rinse Away the Dust

    Now that the bulk of the dust has been removed, move to a sink and hold the filter under warm water or use the spray attachment to remove smaller dust particles. Start at one side and work your way down the filter so that the dirty water runs off of it and doesn't redeposit on the filter.

  5. Wash Away the Grime

    If the filter frame looks dirty or feels sticky, mix a solution of warm water and a few drops of dishwashing liquid. Dip a sponge or soft-bristled brush in the solution and clean the filter. Rinse well to remove any soapy residue.

  6. Dry the Filter

    It is very important to completely dry the filter with a soft towel before reinserting it into any appliance. If possible, place the filter outside or in front of a fan to make sure it is completely dry before reinserting. While you are waiting for the filter to dry, clean the appliance or vent opening where you removed the air filter to get rid of any dust or cobwebs.

  7. Replace the Filter

Replace the freshly cleaned air filter into the appliance or vent. Be sure to latch the opening securely and turn the system or appliance back on.