Home Garden

How to Install My Air Filter

If you have bad allergies, your home's air filter may actually be adding to your suffering instead of helping it. In homes that have forced-air heating and/or central air conditioning, it is imperative to change your air filter at least once every three months. Even more frequent if you have pets! The job of an air filter is to remove the dust, pollen and other allergens from the air inside your home, but if you let the air filter become clogged with dust, you can expect to be sneezing up a storm as your indoor air quality will be worse than standing outside in a haze of springtime pollen. Here is how to install an air filter.

Things You'll Need

  • New Air Filter (properly sized for your unit)
  • Screwdriver (if applicable)
Show More


    • 1

      When you head to the hardware store to purchase a new air filter, understand that they can come in a variety of sizes. Check your heater's documentation to see what size your unit requires. Of course, you can always remove the old one first to check the sizing as well.

    • 2

      The first thing you should do before installing a new air filter is to turn OFF your air conditioning or heater (depending upon the season).

    • 3

      Next, locate the access door for removing your existing air filter. It is usually located in the bottom "L" ductwork, entering the heating unit. It may have a thin, sliding access door or it may be screwed in place. Once you find the access, open it and pull out the old air filter. Look at the filter as you pull it out. On the cardboard siding, there should be an arrow indicating air flow direction. you will want to remember that when you install the new filter.

    • 4

      The size is usually printed on the side of the air filter. It is a good idea to use a permanent magic marker and write the dimensions on the ductwork itself so you will always know what size you need without having to remove the old air filter first.

    • 5

      Now, take the new air filter, and remembering which way the air flow arrow was pointing, insert it into the air filter slot. There should be a channel inside the ductwork that the air filter will follow. Be sure to keep the air filter within that channel.

    • 6

      Replace the air filter access door and that is it! Now, just mark your desk calendar three months from today and you will know when you should replace it again.