How to Locate Your Furnace Filter

Occasionally, as a homeowner, it may be necessary to locate the air filter in the HVAC unit to inspect or replace it. When trying to locate the air filter within the HVAC unit, first check in the mechanical room of the home. The mechanical room is often a closet, space in the attic, or an area of the basement reserved for the house’s heating and cooling equipment. Some suggest switching the thermostat fan setting to “on” and following the sounds to locate the unit.

Where the filter is housed, on or near the unit, will depend of the type of HVAC unit in the home. Many furnace filters are located on the side of the furnace unit. In some furnace designs, it may be necessary to remove an access panel to take out the air filter located on the side of the furnace.

If the furnace has a media filter, or a filter thicker than 1” it may be a “box-type” media filter encased in an air cleaner cabinet. These box-type media filters are usually between 4” to 6” thick. These box or media filters are usually located inside a cabinet or air cleaner that has been additionally installed to work with the air handler.

Air filters are also often located in return air inlet grilles. The return air inlet grilles are usually found in a ceiling or wall and have a hinged-faced inlet grille that makes them easy to recognize. Inside the inlet grille is where the air filter is stored. These are usually quite easy to locate throughout the home. Here, 1” filters are common and they may be located in multiple areas of the home.