What exactly does a furnace filter do?

Home air filters ­also commonly called "furnace filters" ­keep the coils and heat exchanges on the heating and air conditioning system clean. Dirty coils and heat exchanges make the system work harder, so keeping the filter clean helps prolong the life of your HVAC unit.

Some filters also clean the air that you and your family breathe. The variety and amount of particles in your home's air will depend on how many people and pets live in the house and what types of activities go on there. People with allergies or asthma should be extra diligent about keeping home air filters clean.

The most important thing to remember about home air filters is to change them regularly. Even the highest-quality filter can't do its job right if it's clogged with a thick layer of particles it's been filtering from the air. Different filters are meant to be changed at different intervals, but 1-3 month's is a common time frame. Brand new homes, as well as homes where there is remodeling or construction going on, will need more frequent filter changes to compensate for the extra dust and residue in the air.