When and How to Change Your Furnace Filter

December 01, 2015

Caring for your furnace can help more than you’d think in the time in between furnace service appointments. One of the easiest, and critical, ways to maintain your furnace is by replacing your furnace filter. Having a dirty air filter may contribute to a host of adverse concerns for your heating and cooling system, its efficiency, and ultimately, how much your energy costs 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 typically need to be replaced every month and 3 inch filters should be swapped out every three months, depending 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 due to pet dander. If a family member has allergies or asthma, think about replacing your home’s air filter more frequently to help potentially decrease their symptoms.

Now you’re likely wondering how to swap out your furnace filter. Obviously this will change depending on what furnace you have, but typically: 

  • Open or take off the air filter panel close to the bottom of your furnace to expose an open compartment.
  • On the top of that open compartment is where you will find your furnace filter resting on two metal supports.
  • 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 putting in the new filter, check the perimeter of the filter for an arrow that indicates the air flow direction, to be sure you’re installing the filter in the correct direction. In most cases, the arrow should point to the main part (or top) of the furnace. 
At Stark Services, we’ll swap 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.