How to Find the Air Filter for the HVAC System in Your Home

Air Filter
It’s good to remember to clean your air filters so that the filtration stays clean for your home. (BanksPhotos/Getty Images Signature)

I can’t find the air filter in the HVAC unit in the home we just bought. Do all central heating and cooling units have filters?

All central heating and cooling systems should have an air filter, but it can be harder to locate on some HVAC units than on others.

It’s usually located in the return air duct or blower compartment before the return air reaches the air handler. This allows it to clean the air coming from your house before it enters the HVAC unit.


No matter where your air filter is, you need to change it every month during high-use seasons (like summer and winter) and once during the fall and spring. (mphillips007, Getty Images Signature)

Where to Look for HVAC Units and their Air Filters

Common locations for air filters in HVAC units include:

  • On horizontal HVAC units with the return duct attached to the side of the air handler, the filter often fits in a slot on the return air (intake) side of the unit.
  • On vertical air handlers with the return air duct entering on the top of the air handler, it often slides into a slot above the HVAC unit.
  • On vertical air handlers with the return air duct entering below the air handler, it often fits in a slot below the HVAC unit.
  • On other HVAC systems, it may be located behind the return air grill on a wall in your home.
  • On HVAC systems with a return in each room, one may be behind each of the return grills.

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