How To Change a Furnace Air Filter

When I was a kid we didn't have cable TV at our house. So instead of watching cartoons on Saturday mornings, I watched This Old House on PBS. It was my favorite show! Helping people repair or remodel things around the house is one of my favorite things to do.

Changing your air filter is a very simple task, and most people can figure it out without any instructions. But I thought it deserved to be mentioned. My biggest tip for this post is to write down your filter size in the notes app on your phone. I can't stress this enough. I used to put off changing my air filter because I would never know what size to buy. But now, I can quickly look up the filter size in my notes and grab a replacement filter at almost any large retailer.

I know there are subscription service websites where you can sign up to have replacement filters shipped to your house periodically, but I have found those to be expensive. My favorite place to buy replacements lately has been Ace Hardware. They have a pretty good selection of 3M filters. I usually like to get the higher end filters to help filter out any allergens that might be in the air.

You don't have to be at a hardware store to get one. Today I picked up a replacement at Target. The hardest parts about replacing the air filter in your furnace is locating the air filter box, and knowing which direction to insert the filter. Every HVAC system is unique. The HVAC specialist that installed your system had to create the ducts and filter boxes from scratch. So look around the furnace for some kind of opening. Usually the HVAC specialist will write on the opening to make it clear. (Note: Some systems have filters in the air return vents, sometimes located in a ceiling or a hallway. Your HVAC specialist should tell you where the filters are located.)

Once you have located the air filter location, open the filter box door (most slide up or sideways).

There should be an arrow somewhere that indicates which direction the air flows through the filter box. Mine is written on the filter box door. If not, make sure you look at the arrow on the existing filter.

Remove the old filter. This is usually as simple as pulling it directly out. Some filter boxes have little "pockets" that the filter sits or slides into to keep it in place. If needed, take note of the direction of air flow by finding the arrow located on the existing filter.

Insert the new filter by paying special attention to the air flow arrow. This is the most important step! Make sure the filter arrow is facing the right direction when you insert it into the filter box. Then close up the filter box and you're done!

The recommended time for changing your air filter varies. Some systems even prompt you to change the filter based on how long the furnace or air conditioner has been running. I like to change mine at least every 3 months. And look how dirty mine was! Make sure you change your filter regularly to keep your furnace and air conditioner running efficiently.