How to Change Home Air Filters

Changing your heating and cooling system filters should be done once a month to make sure you and your family are breathing the cleanest air and protecting your heating and air conditioning system from unnecessary wear. A dirty filter does not let as much air through and that taxes your system so you use more fuel, whether it's gas or electricity. It contributes to dirt inside the unit as well, which will wear it out more quickly.

Changing the Filter Inside the Furnace Itself

Typical Fiberglass Furnace Filter
  1. Refer to the manual that came with your heating and cooling system to see what kind of a filter you need. Some of these systems come with filters that can be hosed off or rinsed in the sink or bathtub. Others use fiberglass filters that can't be reused. These filters are easily found at hardware, home improvement and even grocery stores.
  2. See if the manual gives you the size of the filter to buy. If it doesn't, use the measuring tape or ruler to measure the dimensions for height, width and thickness. Write these down on a piece of paper to take with you when you go to the store to buy the new filter.
  3. Turn off the furnace and open the furnace compartment where your filter is located. You should not need tools to do this. Most of the furnaces have tabs that hold the furnace panel in place. Just move the tabs so that the panel comes off. You might also look at the condition of the grill panel itself to see if it needs dusting.
  4. Place the new filter in the slot where it goes, and replace the panel. Make sure you put the filter in the right direction. They have an arrow on them that shows you the direction that the filter should go into the unit. If you see the arrow pointing at yourself, it's going the wrong direction. If you are using a permanent filter, make sure you let it dry before you put it back into place and turn on the system.

Replacing a Wall or Ceiling Mount Air Filter

  1. Get a ladder or step stool if your air filter is mounted in the ceiling. Move the tabs that hold the grill panel in place.
  2. Take out the filter and replace it with the new one or clean it with the hose or in the bathtub if it is reusable. Make sure it is dry before you put it back and turn the heating or air conditioning back on. Replace the grill after dusting it off and push the tabs back into place. Make sure the filter is facing the right direction if it is the type that needs to go a specific direction. The arrow on the frame should not be pointing at you.
  3. Turn the system back on at the thermostat.

Things You Will Need

  • Measuring tape or ruler
  • New filter or clean reusable filter
  • Manual for furnace


  • If you or a family member suffers from allergies, you can by or have specially built HEPA air filters for your furnace and air conditioner. If there is no arrow on the filter, you can put it into the frame any direction.


  • Don't forget to clean the filters in the room air conditioners you might be using. These attract lots of dust and pet hair and clog up fast, too.

About the Author

Jackie Johnson is a published writer and professional blogger, and has a degree in English from Arizona State University. Her background in real estate analysis prepared her for objective thinking, researching and writing.

Photo Credits

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