how-to-replace-a-furnace-filter-nonprofit-home-inspectionsThe heating and cooling system in a home is a critical part of a home’s ventilation, air quality, and comfort. The ducts in this system work to transport warm or conditioned air to the air registers throughout the home and the air filter works to trap air dust and other particulates that can damage the blower, as well as lower interior air quality. These systems should be checked regularly to ensure that they are functioning properly.

Regularly changing out your air filter is an important maintenance item that can help to extend the life of the blower as well as improve the overall air quality inside the home. These filters can come in many different sizes, filter levels, and types. The most common type of filter is the disposable type that is discarded when dirty and replaced with a new filter. These are rated by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) according to their Minimum Efficiency Reporting Value (MERV). This MERV rating indicates the porousness levels that go from 1 to 16. Most home filters range from 4 to 13 MERV, with the higher MERV rating removing more contaminants from the air.

There are also electronic and washable air filters that work to remove contaminants from the air. These filters are cleaned periodically and are not thrown out when they are dirty. Most air filters (disposable, washable, and electronic) should be changed or cleaned every 2 to 3 months, depending on the quality of filter, size of the system, and whether the fan is operated in auto or circulation mode.

To change or clean your disposable filter, first find where the filter is housed. Filters are usually installed behind the return air filters, behind a sliding panel at the furnace, or inside the blower compartment. Check the size of the filter and get a replacement of the same size and dimensions. The dimensions are usually printed on the side of the filter (example: 20 x 25). Then, remove the old filter and install the new filter in its place. Ensure the it is installed in the proper orientation, usually the filter will have arrows printed on the sides to indicate which direction air flow should go.

Washable filters can be rinsed in a bathtub or sink and lightly scrubbed with a brush and a mild detergent. With electronic air filters, turn off the power to the filter and wait 30 seconds before removing the filter. Take out the pre-filters and cells and gently clean them with a vacuum. Make sure that both washable and electronic air filters are fully dry before reinstalling them as this can cause damage to the system if they are installed while still wet.