When and How to Change Your Furnace Filter

December 01, 2015

Maintaining your furnace can help more than you’d think in the period in between furnace service appointments. One of the easiest, and crucial, ways to care for your furnace is by switching out your furnace filter. Having a dirty air filter may contribute to a number of adverse concerns for your heating and cooling system, its efficiency, and ultimately, how much your energy costs are each 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 usually need to be replaced every month and 3 inch filters should be replaced every three months, dependent on the recommendations of the filter manufacturer.
  • 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 someone in your family deals with allergies or asthma, consider replacing your home’s air filter more regularly 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 around the bottom of your furnace to reveal an open compartment.
  • On the top of that open compartment is where you will find your furnace filter resting on two metal brackets.
  • There will be a bit of 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 installing the new filter, inspect the perimeter of the filter for an arrow that specifies the air flow direction, to ensure you’re installing the filter in the proper direction. In most cases, the arrow should point towards the main part (or top) of the furnace. 
At Comfortech 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 set up an appointment with us online.