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.

Further Reading

Editorial Contributors
Danny Lipford

Danny Lipford


Danny Lipford is a home improvement expert and television personality who started his remodeling business, Lipford Construction, at the age of 21 in Mobile, Alabama. He gained national recognition as the host of the nationally syndicated television show, Today's Homeowner with Danny Lipford, which started as a small cable show in Mobile. Danny's expertise in home improvement has also led him to be a contributor to popular magazines and websites and the go-to source for advice on everything related to the home. He has made over 200 national television appearances and served as the home improvement expert for CBS's The Early Show and The Weather Channel for over a decade. Danny is also the founder of 3 Echoes Content Studio, TodaysHomeowner.com, and Checking In With Chelsea, a décor and lifestyle blog.

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