Replacing a Furnace Filter

by April Reinhardt
(last updated July 29, 2015)

Originally designed to protect the furnace motor and internal components, furnace filters are housed between the air intake and the heating coil, motor, and fan of the furnace. Furnace filters trap dust that can cause damage to the furnace motor. More importantly, however, furnace filters improve airflow and efficiency of a furnace. Without a filter, the furnace would quickly become clogged with dust, forcing it to work harder to expel air, and eventually overheat and break down. If your furnace filter does become clogged, then its purpose is defeated.

Follow these guidelines to replace your furnace filter once a month:

  1. Locate the furnace filter. Your furnace filter can be anywhere in the space between the return air grill and the air handler. The return air grill is one that draws air in instead of blowing air out. In general, however, the furnace filter is inside of the blower compartment.
  2. Turn the power to the furnace off at the main circuit breaker.
  3. Remove the filter and look for size markings on the frame. If you cannot read the markings, use a ruler or yardstick to determine its size.
  4. Replace the filter the same way you removed it.
  5. Turn the power to the furnace back on.
  6. Purchase the same size filter from your local home improvement store.
  7. Turn the power to the furnace off at the main circuit breaker.
  8. Pay attention to the way the current filter is placed when removing it, and then install the new filter the same way. If the new filter is marked with arrows, make sure that the arrows align with the direction the air is to move through your furnace.
  9. Some units require that you remove doors. When replacing the door, make sure that you replace it tightly as some doorframes engage safety switches that control the furnace.
  10. Turn the power for the furnace back on and check to make sure that the furnace is operating correctly.

Most furnace filters today are disposable, although some are meant to be cleaned and reused. You can purchase furnace filters for just a few dollars, or spend a substantial amount of money for permanent filters and those designed to improve air quality. Most furnace filters are made from fiberglass and are rated by the MERV ranking system, which stands for Minimum Efficiency Reporting Value. The higher the MERV rating, then the more efficient the filter is going to be. Higher quality filters are available to help improve air quality for household members with allergies and respiratory problems and those filters can make a huge difference.

Author Bio

April Reinhardt

An admin­istrator for a mutual fund man­age­ment firm, April deals with the writ­ten word daily. She loves to write and plans to author a memoir in the near future. April attend­ed More­head State Uni­ver­sity to pursue a BA degree in Ele­men­tary Edu­ca­tion. ...

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