When and How to Change Your Furnace Filter

December 01, 2015

Taking care of your furnace can help more than you’d think in the months in between furnace service appointments. One of the simplest, and essential, ways to care for your furnace is in changing your furnace filter. Having a clogged air filter may contribute to a variety of adverse issues for your heating and cooling system, its efficiency, and ultimately, how much your energy costs are month after month.

So what goes in to deciding when you should replace your furnace filter?

  • Type of filter: the two most common filter sizes are 1 inch and 3 inch filters. 1 inch filters usually need to be changed every month and 3 inch filters should be swapped out every three months, dependent on the recommendations of the filter maker.
  • Home habits: if you have pets in your home, it might make sense to switch out your filter more often because of pet dander. If a family member suffers from allergies or asthma, contemplate replacing your home’s air filter more frequently to help ease their symptoms.

Now you’re probably wondering how to replace your furnace filter. Inevitably this will change depending on what furnace you have, but normally: 

  • Open or take off the air filter panel near the bottom of your furnace to expose an open compartment.
  • On the top of that open compartment is where you’ll see your furnace filter resting on two metal lips.
  • There will be a little space to move your filter back and forth that allows you to remove one end of the filter and pull it out of the compartment.
  • When putting in the new filter, inspect the perimeter of the filter for an arrow that shows you the air flow direction, to be sure you’re installing the filter in the correct direction. In nearly all cases, the arrow should point to the main part (or top) of the furnace. 
At Donelson Air Service Experts, we’ll change out standard one-inch furnace filters as part of our regular furnace service Precision Tune-up or PLUS Maintenance Agreement service. Give us a call today at or schedule an appointment with us online.