Air filters trap bacteria, allergens, and pollutants, purifying the air inside your home. As filters accrue dust and allergens, there is a greater risk for allergies and airborne illnesses. Learn how to change air filters and get other practical tips to improve and regulate indoor air quality.

When should I change my air filters?

It depends on the quality of the air filter. Filters are rated for one-month, three-months, or six-months. At a minimum, you ought to replace your filters twice a year. Many factors contribute to how often you may need to replace your air filter including the type of filter, the number of pets and occupants in your home, the quality of air in your area, availability of filters, and price. For maximum safety, plan to replace monthly. With a reusable filter, you may wish to wash and reinstall monthly.

Read more: Best home warranty.

Why you should regularly change your air filters

Regularly changing your air filters improves the air quality of your home. It also provides the following benefits:

  • Prolongs the life of your HVAC system—A clean filter allows for ideal airflow throughout the home. It also prevents your system from overworking and frequently breaking down. This can prolong the life of your system and save you money on repairs and a possible replacement.
  • Lowers your monthly energy bill—Changing your air filter can improve the efficiency of your system by 5%–15%, resulting in lower monthly energy bills.
  • Reduces risk of contaminants—Clean filters trap more airborne contaminants, allowing quality air to circulate throughout your home. This reduces the risk of allergens and airborne illnesses from entering circulation in your house.

Where is my air filter?

Your air filter is a component of your HVAC system and is typically located on the side of the air handling unit—the device that regulates and circulates the air in your home. Changing your air filter is a DIY job and will require 15–20 minutes of your time and a replacement filter that’s a proper fit. You also may have air filters installed in ceiling ducts within your home—you may need a ladder to replace these filters.

To check the size of the air filter, locate your air handling unit or ceiling duct to identify the filter. A metal strip may cover your filter and have a release gauge to free it for replacement. Most air filters have their dimensions printed on multiple sides for easily reading. Write down the size you’ll need—or snap a photo—so you’ll have it on hand at the hardware store. Don’t remove the filter until you’ve purchased a replacement and are ready to replace it.

While most air filters are disposable, some are washable and reusable. Ask the hardware store clerk for guidance or assistance if you’re unsure about which type of filter is currently installed in your home.

How to replace disposable air filters

Once you’ve secured the replacement filter for your system, follow these six steps to change your air filter:

  1. Turn off your system—This is a safety precaution to prevent contact with dangerous electrical material and keep unfiltered air from escaping into your home.
  2. Locate and verify size—Confirm that your replacement filter is the proper size by comparing it to the filter you’re replacing. The new filter should be an exact match.
  3. Remove—Carefully remove the old air filter and avoid dropping dust around the area.
  4. Clean area—Wipe down the vent area with a wet cloth or paper towel to get rid of any dust.
  5. Install—Follow the arrows on the filter that indicate which direction to insert it. This ensures that the filter fits properly and provides adequate ventilation.
  6. Turn on your system—Turn your unit back on and change the temperature on the thermostat by a few degrees until the system kicks on. Let the system run for 20–30 minutes to ensure it’s functioning properly. Reset your thermostat to the desired temperature.

Cover your air conditioner with Select Home Warranty.

How to wash reusable air filters

If you have a reusable air filter, follow these nine steps to properly clean and reinstall it:

  1. Turn off your system—Turn off the central air system as a safety precaution and to prevent unfiltered air from escaping.
  2. Locate and open vent cover—Carefully remove the air filter and avoid dropping dust around the area.
  3. Clean area—Wipe away dust from the vent area and filter frame with a damp fiber cloth or handheld vacuum.
  4. Clean filter—Take the filter outside and rinse it with a garden hose.
  5. Soak filter—Place the filter in a medium-sized tub of water. You may also use a solution of one part vinegar and one part water to eliminate bacteria and allergens. Soak for 1–4 hours.
  6. Remove filter—Remove your filter from the water solution and set it out to dry.
  7. Reinstall—To reinstall your filter, it must be completely dry. This could require you to dry the filter overnight, so plan accordingly as you won’t be able to use your system without the filter installed. When reinstalling, follow the arrows on the filter that indicate which direction to insert it back into the vent.
  8. Turn on your system—Close the vent cover. Turn your unit back on and change the temperature on the thermostat by a few degrees until the system kicks on. Let the system run for 20–30 minutes to ensure it is functioning properly.
  9. Change temperature settings—Reset your thermostat to the desired temperature.

Which air filter should I buy?

There are multiple types of air filters—and even more variety within each category based on quality, manufacturer, and estimated replacement time. Here are the four common types of filters:

  1. Fiberglass—These inexpensive filters are very thin and have a simple flat panel surface for trapping air particles. They typically come in a pack of four to five and need to be replaced every month.
  2. Pleated—Pleated filters last three to six months and remove up to 45% of the air pollutants from your home.
  3. Electrostatic—Energy-efficient, cost-effective, and reusable, these filters will cost more than any disposable filters on the market. However, since they’re reusable, they will last much longer.
  4. High efficiency particulate air (HEPA)HEPA filters are the most effective and efficient and filter at least 98% of air pollutants from your home.

Read more: Choice Home Warranty reviews

Tips for maintaining your air conditioning unit

To ensure your air conditioner functions properly throughout the year, schedule an annual maintenance visit with a professional HVAC service. During this appointment, a technician will check Freon levels, check for leaks in ductwork, measure airflow, inspect electrical terminals, check the accuracy of your thermostat, and perform relevant maintenance.

Here are some other ways to maintain your air conditioning system:

  • Check monthly—If you find that your air filter is dirty or full of grime, replace it as soon as possible.
  • Clean equipment—Keep the air conditioning unit free of dirt and grime to maintain high air quality and system efficiency. If there are bushes or hedges near your unit, make sure they are pruned or trimmed and don’t interfere with the intake fan.
  • Maintain the coils—The evaporator coils are located inside the air handler and can be cleaned by spraying a no-rinse coil cleaner. The condenser coil in your outdoor unit should be cleared of dirt and debris with a shop vac or by hand.
  • Clear debris—Insert a stiff wire into condensate drain channels to unclog them or use a wet/dry vac to suck out any mold or algae growing in larger drain lines.

Read more: American Home Shield review.

Editorial Contributors
Alora Bopray

Alora Bopray

Staff Writer

Alora Bopray is a digital content producer for the home warranty, HVAC, and plumbing categories at Today's Homeowner. She earned her bachelor's degree in psychology from the University of St. Scholastica and her master's degree from the University of Denver. Before becoming a writer for Today's Homeowner, Alora wrote as a freelance writer for dozens of home improvement clients and informed homeowners about the solar industry as a writer for EcoWatch. When she's not writing, Alora can be found planning her next DIY home improvement project or plotting her next novel.

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Roxanne Downer


Roxanne Downer is a commerce editor at Today’s Homeowner, where she tackles everything from foundation repair to solar panel installation. She brings more than 15 years of writing and editing experience to bear in her meticulous approach to ensuring accurate, up-to-date, and engaging content. She’s previously edited for outlets including MSN, Architectural Digest, and Better Homes & Gardens. An alumna of the University of Pennsylvania, Roxanne is now an Oklahoma homeowner, DIY enthusiast, and the proud parent of a playful pug.

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