When and How to Change Your Furnace Filter

December 01, 2015

Caring for your furnace can go a long way in the months in between furnace service appointments. One of the most basic, and essential, ways to take care of your furnace is by changing your furnace filter. Having a dirty air filter can contribute to a variety of unfavorable 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 change your furnace filter?

  • Type of filter: the two most common filter sizes are 1 inch and 3 inch filters. 1 inch filters normally need to be changed every month and 3 inch filters need to be changed every three months, based on the recommendations of the filter company.
  • Home habits: if you have pets in your home, it could make sense to replace your filter more often due to pet dander. If you have someone in the house that suffers from allergies or asthma, think about switching out 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 usually: 

  • 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 supports.
  • There will be a little space to move your filter back and forth that allows you to remove one end of the filter and take it out of the compartment.
  • When adding the new filter, look at the perimeter of the filter for an arrow that indicates the air flow direction, to make sure you’re installing the filter in the right direction. In the majority of cases, the arrow should point towards the main part (or top) of the furnace. 
At Norrell Service Experts, 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 set up an appointment with us online.