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

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? -Paula

Hi Paula,

All central heating and cooling systems should have an air filter, but the filter can be harder to locate on some HVAC units than others. The air filter is usually located in the return air duct or blower compartment before the return air reaches the air handler. This allows the filter to clean the air coming from your house before it enters the HVAC unit.

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, the filter often slides into a slot above the HVAC unit.
  • On vertical air handlers with the return air duct entering below the air handler, the filter often fits in a slot located below the HVAC unit.
  • On other HVAC systems, the air filter may be located behind the return air grill on a wall in your home.
  • On HVAC systems with a return in each room, there may be an air filter behind each of the return grills.

Good luck with your project,


Further Information


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28 Comments on “How to Find the Air Filter for the HVAC System in Your Home”

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  • Debra Says:
    March 17th, 2019 at 10:05 am

    I just moved into a new Townhouse (brand new construction), that is a leased apartment community. I noticed there is no A/C filter in one vent return located above the inside stairs. She said the system doesn’t require one. I wasn’t able to get any more information from her. I’m quite concerned. Can I just take the vent panel off and sit a filter inside it? I haven’t been able to find any information on the internet about HVAC systems not needing a filter. Additionally, I’m a long-term cancer survivor and past history of asthma/allergies, and would like to ensure I’m doing everything to keep my household free of contaminants.

    Please advise….

  • Official Comment:

    Thomas Boni Says:
    January 22nd, 2019 at 9:51 am

    Hi, Verna,
    Some A/C units have a reusable fiber filter that fits into a slot on the bottom of the air handler as opposed to the one that fits into the grill on the wall— although these work, they are not ideal as they filter less air.
    You can purchase the hinged grills that hold an air filter at The Home Depot. You’ll just need to try to match the size of the existing grill opening.
    Good luck!

  • Verna Says:
    January 20th, 2019 at 6:01 am

    Just purchased an 8year old home, just discovered there is no filter in the AC return on the wall. And there is no framing for a filter to fit into to. I know this is not safe, what should we do?

  • Official Comment:

    Thomas Boni Says:
    November 26th, 2018 at 9:28 am

    Hi, Ta H,
    We recommend contacting the manufacturer for product-specific questions.
    Here’s where you can do that:
    Good luck!

  • Ta H Says:
    November 24th, 2018 at 2:41 pm

    First time owning a house with a gas a/c & heat pump unit. Went to change the filter, and there appear to be 2 slots, and the current filter is cross straddled between the two notches. This is an American Standard 2017 model TEM6AOC42H41SAAt with the filter slot horizontal, right under the unit. Any thoughts on which slot to slide it into?

  • Official Comment:

    Thomas Boni Says:
    October 29th, 2018 at 1:18 pm

    Hi, Rudy,
    It sounds like your system needs to be professionally serviced.
    Here’s how to reach Bryant’s Troubleshooting section, which can prepare you for that next step:
    Good luck!

  • Rudy BANERJEE Says:
    October 28th, 2018 at 3:24 pm

    BRYANT 310AAV024070 (for heating) & BRYANT 113ANA24 13 SEER (2ton AC) was installed recently. Can’t find the air filter. Please help. Regards, Rudy

  • Official Comment:

    Thomas Boni Says:
    December 8th, 2018 at 4:09 pm

    Hi, Lisa,
    Danny says, “It sounds like either the thermostat is failing or a relay in the heating system itself. I would suggest calling in a professional who can diagnose the problem very quickly. Good luck!”

  • Lisa Graves Says:
    October 21st, 2018 at 1:45 pm

    Not sure if mine is a filter problem because the return filter is replaced in my hallway often. The unit is about 5 years old. We recently switched the thermostat from cooling to heat. I noticed the fan was staying on and the room temp wasn’t getting that much warmer so I checked the thermostat and saw Aux Heat instead of Heat On under the temp I set it for 72. The inside temp says 64….very chilly in here right now! I looked up what Aux Heat meant and it was a scary description due to it comes with monstrous bills! I shut the unit down and put some socks on for now. I’d rather layer up that run up a bill. Any suggestions on why it is reverting to Aux Heat or how I can stop that? I’m in Virginia and the weather is just now cooling down so no freezing outdoor temps are a factor. Thanks!

  • Lillian Schaeffer Says:
    October 8th, 2018 at 5:01 pm

    Thanks for letting me know that there are air filters behind each return grill in your home. My husband and I have noticed that our air conditioner isn’t running as efficiently as it usually does—it hasn’t been cooling super effectively, and our energy bill has also increased quite a bit. We’re thinking that it might be due to air filters that need to be replaced, so we’ll definitely check all of those filters.

  • Dr. Bill Underwood Says:
    August 20th, 2018 at 9:54 pm

    Carrier Model153E35AXXX Serial #; 1310101165 Register No. Given when parts were sent :668 8311. We had this unit installed about 4 years ago–If you can find a filter with these numbers typed by an 80 y/o man after a glass o, I would like to commend youf wine

  • Official Comment:

    Thomas Boni Says:
    August 5th, 2018 at 4:03 pm

    Hi, surinder,

    You know what they say — a picture’s worth a thousand words! Please send photos to so we can better understand your situation.


  • surinder Says:
    August 5th, 2018 at 11:51 am

    HI I have a heat pump in my attic since my ac is working but not blowing cold air but I could not find any filter there so i could clean to get cold air please help

  • Deborah Says:
    July 31st, 2018 at 7:57 pm

    I have the same issue as Donald. My return is sealed shut. So I have never known if there is a filter or not.

  • Official Comment:

    Thomas Boni Says:
    July 26th, 2018 at 12:36 pm

    Hi, Mysti,

    We recommend contacting the manufacturer for product-specific questions.

    Good luck!

  • Mysti Says:
    July 24th, 2018 at 8:03 pm

    We have a Sierra air conditioner on the roof where do we locate the air filter on that unit

  • Donald Says:
    June 23rd, 2018 at 8:10 pm

    There is still a question that I have about air filter location. All I hind in my small one story house is what I guess is the return that is about 2X3 ft and tightly secured to the wall. Every other house I’ve lived in had an overhead filter. These were easy to see and change. That’s why I’m wondering if I’ve found the filter.

  • Daniel Gonzalez Says:
    May 29th, 2018 at 11:22 am

    I also have 2 returns(up&down stairs) but I located the spot on the handler in the attic where in a video shows where it she be but nothing? Had the original looking AC tape? Thank you for any guidance

  • james daffron Says:
    March 8th, 2018 at 3:33 am

    need heat pump return air filter 35x32x1

  • Official Comment:

    Thomas Says:
    February 26th, 2018 at 8:11 am

    Hi, Kathy,
    This guide should help you find the furnace filter. Give it a read and let us know how it turns out!
    Thanks for watching.

  • kathy Says:
    February 21st, 2018 at 1:10 pm

    I want to change my furnace filter. I can’t find any filter on my furnace. I can see an air scrubber attached to the furnace…..I really don’t know what an air scrubber is. We have looked for any kind of filter and can’t find one. This is a manufactured home. I do not know how old the furnace is. It is an Amana.

  • Tammy Says:
    August 25th, 2017 at 12:49 am

    My son took the filter off his AC unit. Not sure why or for how long. But the land lord says it has done damage to the AC. Which froze up and thawed out and isn’t working. Is this possible. Can not using a filter harm the unit. I believe it has only been off a couple days.

  • Zequek Estrada Says:
    October 10th, 2016 at 2:28 pm

    Danny, you’re a life saver. I was panicking since I’ve had a similar problem as Paula. It’s comforting to learn that it might just be harder to locate the right kind of air filter.

  • Debbie Says:
    June 15th, 2016 at 2:52 pm

    do I really need in line vertical air filter and room wall inlet filters. the in line filter is 4inches thick and each room filter is 3/4 inch thick. isn’t this too many. all I need is the in line filter?

  • kile Says:
    May 5th, 2016 at 11:11 am

    I wont to know if I have a filter on my AC air handler that is located in my atac which is separate from my condenser unit. I do have two return ducts that do have filters. but im not sure if the air handler its self may have a separate filter that also should be changed every season the hole unit is only 4 years old. THANK YOU I hope you can help me and may be give me and idea of where it is located

  • Jim Coker Says:
    January 23rd, 2016 at 9:11 am

    I can’t seem to find the air filters on the horizontal gas heat unit in my crawl space. I did see grill panels with wires and tubing but nothing that looks like it belongs to a filter function. I did find filters inside the house. I called the Goodman Mfg. and they have no clue. The unit was made in 2000 and don’t know who installed it…any ideas?

  • Buddy Says:
    February 13th, 2015 at 11:55 am

    Wife and I having a few allergy problems. We have Aprilaire filters installed on both hvac units. I have made a visual inspection of vents and returns and they seem pretty clean. Recently had one of the hvac units replaced.Should I have vents cleaned? I’ve seem so much negative information about this that I not sure whether to invest money in it.

  • Tony Tewell Says:
    September 10th, 2011 at 10:26 am

    I have a heat pump central heat and air system in my new home; it’s located in the attic. The return vent in the ceiling has a filter. When I inspected the unit, I noticed a slot for a filter there too. Should I place a filter in the unit as well?

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