How Long Does a Furnace Filter Last?

Oops! Looks like this image is too cool for alt text!

By Tom Moor

Posted 8/1/23

The lifespan of a furnace filter varies depending on the kind of filter you have plus the indoor air quality in a home or office. If you aren’t sure about your furnace filter lifespan, contact our customer service team for assistance at 855-932-4822.

What Does a Furnace Filter Do?

The furnace filter is essential for keeping your heating and cooling system clean. The air in your home is pulled into the return ductwork via the blower fan, so it can be heated or cooled and pumped back into your home. The filter is responsible for cleaning the air that is pulled into your unit before it comes into contact with expensive components inside your HVAC system. Furnace filters capture:

Dust mite debris
Mold spores
Pollen
Smoke
Pet dander
Smog
Household dust

Typically, your furnace filter is located inside the blower compartment. If you can’t locate your filter, call a professional to assist you, so you don’t damage important components inside your system.

Types of Furnace Filters Available

After you have located your furnace filter, you need to determine the type of filter you already have installed in your unit. The different types consist of:

HEPA filters are high-efficiency particulate air filters and remove up to 99% of particles that are 0.3 microns or larger.
Pleated filters cover more surface area for particles to be captured within its pleats.
Electrostatic filters are semi-permanent, washable filters carrying an electronic charge to attract dust particles.
Fiberglass or synthetic filters are the most popular filters for furnaces and are great at protecting your heating and cooling system against large dust particles.

When Should You Replace Your Furnace Filter?

Each furnace filter has different recommendations for when they should be changed. Some are even reusable and require you to just wash them and put them back in your furnace. The general rule for filter replacement is once every 3 to 6 months. Thicker filters don’t have to be changed as often, such as 6-inch filters, which can last between 9 to 12 months before they need to be replaced. For a loose frame of reference refer to this chart:

1″ Furnace Filter: 1 – 3 Months
2″ Furnace Filter: 1 – 3 Months
3″ Furnace Filter: 6 – 9 Months
4″ Furnace Filter: 6 – 9 Months
5″ Furnace Filter: 9 – 12 Months
6″ Furnace Filter: 9 – 12 Months