When and How to Change Your Furnace Filter

December 01, 2015

Maintaining your furnace can go a long way in the months in between furnace service appointments. One of the most basic, and essential, ways to care for your furnace is in replacing your furnace filter. Having a clogged air filter could contribute to a variety of negative issues for your heating and cooling system, its efficiency, and ultimately, how much your energy expenses are every month.

So what goes in to determining when you should switch out 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 replaced every month and 3 inch filters should be swapped out every three months, based 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 as a result of pet dander. If you have someone in the house that deals with allergies or asthma, consider changing your home’s air filter more frequently to help ease their symptoms.

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

  • Open or pull off the air filter panel around the bottom of your furnace to uncover an open compartment.
  • On the top of that open compartment is where your furnace filter is resting on two metal lips.
  • There will be a small amount of space to move your filter back and forth that allows you to pull down one end of the filter and take it out of the compartment.
  • When installing the new filter, look at 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 proper direction. In most cases, the arrow should point at the main part (or top) of the furnace. 
At Comfort Masters Service Experts Heating & Air Conditioning, 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 arrange an appointment with us online.