When and How to Change Your Furnace Filter

December 01, 2015

Caring for your furnace can go a long way in the period in between furnace service appointments. One of the most basic, and essential, ways to care for your furnace lies in replacing your furnace filter. Having a dirty air filter may contribute to a host of adverse problems for your heating and cooling system, its efficiency, and ultimately, how much your energy costs are every month.

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

  • Type of filter: the two most common filter sizes are 1 inch and 3 inch filters. 1 inch filters typically need to be replaced every month and 3 inch filters need to be swapped out every three months, based on the recommendations of the filter manufacturer.
  • Home habits: if you have pets in your home, it may make sense to switch out your filter more often because of pet dander. If a family member has allergies or asthma, contemplate replacing your home’s air filter more regularly to help potentially decrease their symptoms.

Now you’re probably wondering how to swap out your furnace filter. More than likely, this will differ depending on what furnace you have, but usually: 

  • Open or take off the air filter panel near 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 little space to move your filter back and forth that allows you to bring down one end of the filter and take it out of the compartment.
  • When adding 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 proper direction. In nearly all cases, the arrow should point to the main part (or top) of the furnace. 
At Mountainwest 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.