Replace HVAC Air Filter


The air filter on your HVAC (Heating, Ventilation and Air Conditioning) system needs to be replaced every 1-3 months to keep the air in your home clean and flowing freely through the unit. For best results use a high quality air filter that’s rated to remove mold, pollen, and other microscopic particles.

The air filter is usually located behind the wall or floor air return grate. In some systems the filter may be in or near the air handler unit. If you have trouble locating yours, check out our article on How to Find the Air Filter in Your Home.

To replace an air filter:

  1. Turn the heating/cooling system off, and wait until it stops running.

  2. Take the cover off the air return.

  3. Remove the old air filter.

  4. Write the current date on the new air filter.

  5. Insert the new air filter in the return, making sure the arrow on the edge of the filter is facing in the direction of air flow. For filters with wall and floor mounted returns, the arrow should point in toward the return duct. For filters mounted in the ductwork near the air handler, the arrow should point toward the HVAC unit.

  6. Put the cover back on the air return.

  7. Turn the heating/cooling system back on.

To make it easier to replace next time, put a sticker on or near the return with the size filter you need to buy and when to replace it.