Have you ever experienced problems when replacing a furnace filter? Well, you’re not the only one! We’ve all experienced it at some point. Remembering when to change your air filter is one thing, and when it’s time to install it, you’re not sure which direction the air filter arrow should point.
Should the airflow arrow point up or down?
No matter how much research you do, you may not find the answer you want. However, the answer to this question is simple.
The arrow should always point in the direction the air is flowing.
Alex, our in-house air filter expert, has this to say about which way the air filter should be installed:
“You need to verify which way the air flows, and the arrow should point in the direction the air is flowing. If the air is not flowing, briefly turn the fan on to verify the direction.”
Like many, you may be wondering why the arrow should point in the direction the air flows. The answer lies in the way the air filter is built. The front side of the filter is the “filter media,” commonly called “pleats.” The back side usually has a metal mesh or a cardboard frame on some filters. The back of the filter is built as a support system for the front of the filter. You need the air to push the media (front side) into the metal mesh (back side) for proper support.
What Happens if You Install Your Furnace Filter the Wrong Way?
Improperly installing your air filter might not seem like a big deal, but it can negatively impact many things. When your furnace filter is installed incorrectly, your air quality will be poor; it can cause your HVAC system to not run as efficiently, lead to more frequent filter changes, and potentially damage your furnace.
How Can I Tell If My Furnace Filter Is Installed Incorrectly?
There are a few ways to tell if you’ve installed your air filter wrong. Here’s what to look for:
- Dirt and Dust Accumulation: If you notice a dirt and dust build-up on the filter’s metal side, it’s been installed incorrectly. The metal mesh side of the filter should remain clean when using a pleated filter.
- Airflow Arrow Direction: If your filter has an airflow arrow on its frame, it should point toward the wall or the furnace, not toward you or away from the furnace.
- Noise: If you notice noises coming from your return or furnace when it is running, it could be a sign that your filter is installed incorrectly.
- Decreased Efficiency: A clear sign that you’ve installed your filter wrong is if you notice a drop in your system efficiency. If your furnace is running harder or your energy bill is higher than usual, check to ensure you’ve installed your filter in the correct direction.
Taking a few extra seconds to ensure you’ve installed your filter correctly will save you time, money, and frustration in the long run.
What To Do If You’ve Installed Your Furnace Filter Incorrectly
If you’ve identified that you’ve installed your filter incorrectly, the first step is realizing it! Now is the easy part, correct it! Turn off your furnace before you pull your furnace filter out. Look at the filter and ensure the mesh side points away from you or your furnace. And reinstall it! It’s that simple. If your filter seems dirty, replacing it with a new one is best.
How Do You Know If You Have The Right Size Filter?
The right size filter is as important as ensuring it’s installed correctly. To ensure that you have the right size, check out 3 Ways to Find the Air Filter Size You Need.
Where to Buy Replacement Furnace Filters
Now that you know which direction the arrow should point and why it should point in that direction, you’re ready to order your replacement air filter.
Are you looking for high-quality pleated air filters without the crazy price tag? Filters Fast® Brand Air Filters are the perfect option! Available in MERV 8, 11, and MERV 13, our pleated furnace filters are affordable and delivered right to your door!
AC filters should be changed at least every 3 months, so having extras on hand is always a good idea. If you’re unsure which air filter best fits you, see Three Questions to Ask Before Buying Your Next Air Filter for additional help.
As always, Filters Fast is here to assist. If you have any questions about which air filter you should choose, feel free to ask below, and we’ll be more than happy to help.
Katie says
Cecelia,
Thank you for reaching out to us. The metal-mesh will always serve as a backstop for the filter media. We created the following diagram (please use link below) that shows the proper orientation. This accounts for both possible directions of air flow.
https://drive.google.com/file/d/1u1dYIVvemA3kZmi4I-qRbZXOnCTikO1K/view?usp=sharing
This being said, it is possible there could be a manufacturer defect that causes the arrow to point in the wrong direction. Please email [email protected] with an image so we can forward along. Thank you!
cecelia dowling says
bought filtrete ac filter from walmart. If I installed it the way the arrow points for air flow it would be backwards. The metal mesh would be facing out not toward the blower motor. This is not acceptable.
But I guess you think I’m stupid.
Katie says
Darlene,
That is a great question. The arrow should point towards the return or furnace. If your return is in the wall or ceiling, the arrow should point towards the wall or ceiling. If your filter needs to be changed in your furnace, the arrow should point towards the furnace. Please let us know if you have any additional questions.
Darlene Ann Krug says
my furnace filter looks the same on both sides, pleated material with wire mesh on BOTH sides which confuses me. It still shows one air flow arrow on the side. Can the filter be inserted either way, up or down?
Katie says
Lisa,
It is possible the airflow arrow was mislabeled. We would recommend reaching out 3M Filtrete directly. We are sure that they would appreciate your feedback.
Lisa says
I just bought a new pack of 3M Clean Living Filtrete filters. When I installed one of these new filters, my air conditioner stopped working and was struggling to get air in. It would run all day and not cool the house. When I took the filter out is was bent inward. The airflow arrow was facing the right way, but the metal mesh was on the wrong side of the filter. Is it possible the airflow arrow was labeled incorrectly? I turned the filter around and now everything seems to be OK.
Katie says
Paula,
That is a great question. If the filter is located in the ceiling, the arrow should be pointing towards the ceiling. Please let us know if you have any additional questions.
Paula says
If the filter is located in the ceiling of a central air conditioning unit, in what direction should the arrow be pointed?
Katie says
Katie,
That is a great question! Are you changing your air filter in the wall or ceiling? If so, the arrow should be pointing towards the return, not towards you. In most cases, you should not be seeing the metal grating after you have installed it. If your filter is located in your furnace system, the arrow should point towards the furnace.
Katie says
Rita,
If your filter slides into your furnace, the airflow arrow should point towards the furnace. If where you change your furnace filter has a grate or grille, you will point the arrow towards the return (away from you).
Katie says
If I point the filter in with the arrows pointing toward the unit, the metal grating is on the outside. Could the arrows be wrong? Which logic should I use? Arrows, or metal grating facing unit?
Rita Bruton says
My filter slides in flat. Do arrows go up or down. Unit is outside and inside in closet. Air comes out ceiling vents. So which way does air flow, up or down from filter?
Katie says
Ethel,
Thank you for reaching out to us. The arrow points in the direction of the air flow. Since the air is being pulled up into the vent the arrow should also point up.
Ethel says
I have a ceiling air condition/heating unit. I purchased a Honeywell (AAF Flanders) air filter and noted that next to the words Air Flow the arrow looks like it is pointing down. I placed a plastic bag next to the vent to see which way the air pulls and since the bag stuck to the vent, I’m assuming the air is pulling up. I put the filter in with the words and arrow facing down but wonder if this was or is correct since I researched this online and it seems like the filter should be going in with the arrow facing up. I did this because I started to get a drip from the opening that is over my tub. I did have the unit cleaned and drained less than 6 months ago so I thought maybe I put the filter in wrong. I since have put it in with the arrow up. Is this correct. Thx
Katie says
Anita,
Thank you for reaching out to us. We found information that indicates the Space-Gard systems can be installed vertically or horizontally [not sure if we have the option to share an image~see info box]. We are sorry to say we do not see a reference to the blinking light. We would recommend reaching out to Aprilaire to confirm this information for your particular model. https://www.aprilaire.com/contact
Anita Bruckner says
I am asking which way our spaceguard filer should be installed ina verticle position on our new Bryant 915SA. We have always had the media with the filer spacers on top. Is this the proper air flow on our new furnace. As I stated, a verticle position above the furnace. Also, sometimes our furnace has to run twice in a row. I have noticed an amber light blinking. Any concern
Katie says
Latoya,
Great question! The pleats should be facing you and the wire should be faced towards the inside of the return. Look for the airflow arrow on your filter and make sure that it is pointing towards the return. Here’s a quick way to remember it: The grid is on the back to keep the filter media from being sucked through. Please let us know if you have any more questions!
Latoya says
Which way should wire show on air filter if placing in ceiling? Should I see wire or pleats from outside of vent?
Katie says
Dennis,
Thank you for reaching out to us. Air units will pull in air from one side and blow it out on the other. Please review the unit to confirm where the filter is installed. Most of the time filters are installed on the side where the air is being pulled in. For this application, the arrow points towards the unit. The direction of airflow would be from the room, through the filter, through the heater, and out through the vent(s).
Please let us know if you have any additional questions.
Katie says
Jose,
Thank you for reaching out to us. We are happy to research that for you. Please provide the part number or link to the product page for the product in question.
Jose M Rivera says
What is the air flow direction on a MERV 8 hvac 1” roll air filter orange & white ?
Air goes in on white side and out on the orange or in on orange and out on white ?
Katie says
Jermon,
Thank you for reaching out to us. We would recommend reaching out to the manufacturer of the filter to confirm. It is likely that is a manufacturing error. Normally the arrow points from the pleated side to the wire side. The metal grid support is on the back and helps the pleats maintain their shape.
Jermon says
The arrow on my filter is facing away from the wire side. Should I insert it the way it is saying?
Katie says
Bert,
We appreciate your feedback on our video. This video was made years ago and we are working on updating it.
For future reference: The arrow points towards the system; this will be true for all return vents. *A return vent is one where the air is being sucked into the HVAC system. Another way to look at it is that the grid is on the back to keep the filter media from being sucked through.
Thanks!
Bert C says
A simple drawing with filter showing which way the arrow should point, whether it is the floor, on the ceiling or in my case on a high wall would be suffice. I don’t think the video with the bear appeals to intelligent adults. Maybe the kids like the bear, if they are the ones changing the filter.
Katie says
Debbie,
Thank you for reaching out to us. Yes, this will be true for all return vents. A return vent is one where the air is being sucked into the HVAC system. Another way to look at it is that the grid is on the back to keep the filter media from being sucked through.
Katie says
Hi Melissa,
Thank you for reaching out to us. The arrow points towards the system; this will be true for all return vents. *A return vent is one where the air is being sucked into the HVAC system. Another way to look at it is that the grid is on the back to keep the filter media from being sucked through.
Melissa says
My air filter is in my hallway ceiling.. Which way to the arrows need to point ? I keep getting conflicting information… Arrows pointing out to the room, or up towards the equipment? I assume into the room —please advise … thank you so much!
debbie says
Mine is in the floor. Does this still ring true that wire side goes facing into floor vent
Katie says
Hi Mary,
Thank you for your feedback on our video. The wire part will face the inside of the return and the pleated part without wires will face outwards (this is the part that you will see). In most cases, the arrow on the filter should be pointing to the inside of the return. Please let us know if you have any more questions!
Mary says
Your video is silly and unhelpful! Please specify whether the arrow faces (goes toward) the ceiling or the floor. Thanks.
Katie says
Hi Dawson,
The wire part will face the inside of the return and the pleated part without wires will face outward (the part you see once installed).
Dawson says
Hi does the cross crossing design face the big open hole and the pleats face me standing in front of it
Kory says
The arrows go towards the ceiling, into the return.
mary says
I still have no clue. Have no idea of airflow. vent is in hallway ceiling and the filter that came with house looks like dog potty pad, no pleats, no arrows, no nothing. Do arrows go towards ceiling or floor on new filter?
William says
There are no arrows on my filter. It is just a cut sheet of fiberglass.
There is nothing on the package to indicate which was it should face. Does the coarse side go toward a/c unit or toward the hallway?
Kory says
Hello, does the filter have arrows on them? If so, the arrows point in the direction of the air flow.
Thank you,
Sheila says
I have a filter in the hallway ceiling. Should pleats be facing hall or up in attic where air conditioner is? No clue.
Kory says
Hello Tim, the arrow shows the way the filter needs to be inserted, into the return.
Tim Murdock says
I have a 3M basic pleated filter and it shows the air flow arrow pointing opposite the wire mesh side.Either I’m an idiot or it’s a rare manufacturing fault.
Kory says
Hello Sue,
Do you have arrows on the filter? If not, the pleats face out to the hall.
Thank you,
Sue says
My filter is on the lower wall outside of furnace. The heat vents on ceiling. Which way do the pleats face? Towards the furnace or out to hall?
Kory says
Hello,
The arrow should point in.
Thank you,
Kory says
Hello,
Do you have pets or smoke in your home? If so, we recommend starting with a MERV 11 filter. If you do not have those elements in your home, a MERV 8 will suffice.
Thank you,
Kory says
Hello Ginger,
The arrows should point into the house.
Thank you,
Kory says
Hello George,
The arrow needs to go in the direction of the air flow through the return.
Kory says
Hello Robert,
The arrow should point in the direction of the air flow.
Robert White says
My filter says the arrow should point towards the blower is this correct
George says
Hi-When changing my air conditioner/heating unit system(south FL)that is located next to the celing inside the garage,where the condenser resides, does the indicating arrow goes back toward the condenser??.I would appreciate your help-Thanks
Tammy says
Here’s how my A/C son said to remember. If your air vents are in the floor the arrow points down. If the air vents are in the ceiling the arrow points up.
Ginger says
My air filter is outside where big fan blows the filter slides in right next to big fan and right before unit meets the outside of house so which direction does arrows face? The house or away from house?
charbedu says
I have two returns on my ceiling for my a/c. I am in a high rise building (an older building and the main a/c unit is in the basement). I need a custom made pleated air filter for both these returns. What would be the best Merv number to get. I am close to the beach if that makes any difference. Measurements are 17-1/8 X 33-1/8 X 1 inch?
Madci says
My return is in the wall. Does the arrow Point in or out. Thanks
Kory says
Hi Fran, the arrow must face toward the furnace and away from the return duct that carries the air in need of cooling and heating.
Fran Lange says
On a furnace filter–is the arrow towards the unit? This is a side filter.
Kory says
Hi Robert, the arrow should be pointing up toward the ceiling.
robert says
My vent is in the floor what way should the arrow be pointing up toward the ceiling or down in to the vent
Kory says
Hi Lou, the arrows should point in the direction the air is flowing. For example, if the air is flowing down to the floor, then the arrow should point down as well. This blog can help provide insight: http://www.filtersfast.com/blog/index.php/2013/06/which-way-does-air-filter-go/. As for your other question, a MERV 8 will do just fine. A MERV 11 is generally more recommended for better filtration, but this can vary depending on the air conditioner unit. If you have been recommended a MERV 8, then it is best (and advisable) to stick with that MERV Rating.
Lou vanderoord says
OK, So, when I replace my ceiling filter ,which way should the arrow point
toward the ceiling hole ? Up pointing to air hole ?
Or down pointing to the floor?
By the way ,my house is carpeted.
has two air conditioners Armstrong ,one on each side outside of the house
It has been recommended that I use No higher than” Merv 8″for my inside air filters.
There are so many different air filters to look at in stores with very
different price ranges . Very confusing to decide ,which will do the job.
Is Merv 8 best to use?
Kory says
Yes Tony, that will be a good assumption!
tony says
concerning air flow, can I assume the air flows from the heating unit out?