Universal HVAC guy here, for some 20 years now I've been using painters tape and I keep a small sharpie near my filters. The painters tape is great for sealing up gaps and doesn't leave a residue and I also keep a strip of painters tape on the front panel and write down the date of every filter change. Painters tape is very cheap and removable. Also, when you remove the painters tape it pulls out my filter when I lift the tape off.

As a retired HVAC industry professional, I wholeheartedly agree and congratulate you on your excellent, accurate video. There are other issues as well, but are beyond the scope of your video. Proper air duct sizing has become a lost skill in the trade. The return air duct should be sized by the volume of air AT a LOWER velocity so the air filter can catch the airborne particulates. Like a bullet, the higher the velocity, the easier it penetrates or passes thru an obstacle, in this scenario, a filter. Secondly, the square throat on the return duct (where you see the sheet metal makes a 90 degree turn towards to furnace) is a big problem as it creates great turbulence/ pressure drop there and thru actually cuts down the amount of of air moving. Example: if you have ever removed a filter and noticed a part of it was totally clean while the other half or three quarters was very dirty THERE IS the PROOF the little to no air was moving thru the filter at that point. That SQUARE THROAT is the reason. Google proper air duct fittings design and see. Thank you for reading this.

Thank you for recording and posting this valuable educational video.

Thanks for taking the time to make me aware of the leaks and scheduling 👍🏽

Finally a video on an open slot where the filter goes. I kept looking for a door or face to open to look for a filter but instead there's that open slot in the back where a filter SHOULD be but is not. After living here more than 2 years apparently WITHOUT a filter in place. The a/c has always worked well but the unbelievable dust in my house, especially the bedroom was too much. . Thanks to this video I may be able to fix my situation

Thanks so much for this video. I formed a cover from a slightly-damaged magnetic return-vent cover I had laying around. Works great!

As a retired HVAC contractor using magnetic vinyl worked well, I would put the size of the filter on it for easy reference. On heat pumps with marginal duct size I wouldn’t recommend anything greater than Merv 8

Oh man, first time homeowner (and AC owner) and this video was a life saver. It's the most visually clear and detailed explanation of something so aggravating simple! Big thanks.

Thank you! Our home's filter covers were both mangled by the previous owners and this solution is perfect.

I appreciate the link for the seal. This has bothered me on my furnace. It is also worth noting that the opening may be on both sides. (like mine). I have always pushed the filter against the furnace side, but that was not a solution. Having an AC evaporator makes this more crucial as it acts as a non accessible filter. Mine was plugged solid when I bought my house. Excellent video

Thanks for the explanation about the arrow.

Great video, just replaced mine and feel 100% better already.

Thank you for actually explaining the entire situation instead of the other videos I watched that only made me more confused! Im subscribing right now n❤

So that's why the furnace installers tried to fashion a cover for this gap with extra sheet metal! I had no idea it was so critical. Ordered the covers, thank you!

My heating and air guy recommended I use the lower Mervyn filter with my unit. I don't recall the specifics other than better air flow for my setup. There is a gap, and sometimes I hear the filter bang when the air is sucked through. I have a dusty old basement even though I do keep an air purifier running 24/7. Anyway, I am ordering this air lock! Thanks for this tip.

I used blue painters tape in the wide width. Cheap, efficient and I mark the date with a black sharpie.

If your buying on line there is a way to drop the cost of filters buy buying them in a box of ten or twenty at a time and it about half's the cost, set the change of the filter on your phone.

Best video on this subject. Thank you very much.

Thanks for posting this informative video. I've been using a good quality duct tape for years with no problems.

This was a great video and exactly what I needed! Thank you sir.

Thank you so much for this valuable information!

Super clear and useful info, thanks so much!

Great information to share! Thought - since you will be removing the seals to change the filter I would suggest marking the one you cut with a sharpie or even electrical tape

Thank you. I do need this product.

Thank you for posting this helpful video

I like that brick and a support for the furnace

This is good information for sealing a certain part of the HVAC system. I went a step further and used mastic on the seams of the HVAC unit, metal ducting and inside the vents in each room. Additionally using expanding foam to seal around each vent and using a metal foam delivering gun to minimize expansion. Cost me less than $70 and if you can paint, you can apply mastic. I use a 5 inch merve 8 filter, and my Goodman HVAC is coming up to 24 years old with no issues with annual servicing. I run an average stand alone air cleaner in my bedroom and one in the main area of our house, 24/7, and it costs pennies per day. Dust and airborne particles are virtually non existant in our house, even when we open up the windows during the day in fair weather, which is about 8 months out of the year in Southern California.

It also causes a negative pressure in the furnace room. You can end up with a back draft on any other gas appliances in the room.

good info, unfortunately my furnace has a weird offset so I can't use this filter seal. however, I was able to fashion my own homemade seal using some scrap paneling wood that I had saved and duct tape! I also stapled some old towel material on the inside and it effectively sealed off the draft! I also changed the filter and noticed a lot more dust/debris on the edge where the draft was sucking in the basement air, so thanks for the vid which gave me the ideas! 👍👍

Great tips! It's amazing how many homeowners don't have a clue. My neighbor didn't change her filter for 4 years.😳 I almost couldn't get the filter out. They didn't know you have to descale the tankless hot water heater as well. It's people like that, that don't maintain their cars also. Just subscribed, looking forward to seeing your other content.

Great product affordable solution, thanks for info.

Good product review and demonstration.

Ordered. Thanks for the tip. I knew that gap was an issue but I didn't know a cheap way to fix it. For filters, I have to order a custom size from a filter company.

I almost didn’t watch this. I’m so glad I did. Solid info and I didn’t care it was 10minutes.

Pretty much any tape that can cover the gap will do the same thing. Other thing about this video is the frame on the furnace side of the filter is bent. If it were straight, the negative pressure caused by the blower will suck the filter against the furnace and pretty much seal the gap and cause all the air entering to go through the filter. So, even with your plastic and magnet solution, all that's going to happen behind the plastic is air will now flow around the filter, in the space between the plastic and the filter, and enter through the damaged frame.

Ok Scott your amazing... Keep up the good work..

Thank you very much for this useful information.

Aye lad well done me bhoy! I Chang ours 30 days or less depending on heavy useage. Love your wisdom lad keep it up

Thank you for this. The magnetic seal is just long enough to completely seal my 25x20x1" filter that drops in longways from the top.

Thank you. Got the answer I was looking for @2:05. Then watched the rest.

I have that exact HVAC model! When the blower comes on, the filter is pulled tightly against the frame, so the "gap" is only on the return side, thus all air goes thru the filter element!

Wow, I learned a lot, thank you!

I think it depends on the filter. The MERV, the size etc. The 1 inch, seems you should change them more often. I now have a 5 inch, and it says 6-12 months depending on air conditions. I use MERV 10-11 as more than that, seems too restriction on my system. I also have a filter box, which is a box separate from the duck and the furnace which houses the filter. Not sure If i have this because I have the 5 inch filter. When I got my new furnace, the furnace company suggested i install a filter box, but when the did the home inspection, noticed I had one so removed it from the quote and reused my current one.

I like taking a bit of air from the basement and running it through the filter and A/C. I cut a 4" hole in the return at the basement floor, and taped a piece of filter material and a piece of carbon filter over the hole. My basement air improved exponentially, and I only noticed a tiny bit of basement smell the first day or two. Now my basement is so much dryer, and it doesn't smell.

I figured this out about a year ago because we kept getting dust every other day. I was told if I didn't figure out a solution I'd be the one dusting. I tried some 2" wide masking tape and thankfully it worked. It really does help keep the dust in the basement. Thanks for another great tip.

Good video and great tip about the filter seal; just placed my order!

Great video, as usual. You do a good job with the level of explanation - not too technical, but technical enough to understand and get the job done. Keep them coming! Happy New Year!

nice product ! good job very easy !

Great video!Can you do information about thermostats and sump pumps

I use an Aprilaire whole home filtration system on 2 houses. Merv 13, filter is changed annually. Much better than those thin filters.

Thanks I have the same problem

Blessed with a 6inch thick filter on my HVAC setup

Interesting. Thank you!

Thank you that was a great trip

very clear video, using this

I sold filters among other things for 8 years and I always told folks basic is the way to go.The filter is not for you it's for the unit.Less carpet in your home more often you should change it ,you would be surprised how much dust it holds.Also tape around the frame of filter to help it seal,and if you're like me with a 20×40 return and have to use 2 filters seal the center.I change mine every 30days,and have a purifier in every room of house due to having pets.

Another method that I use is to install an adhesive backed half round weatherstrip on the duct side of the opening, to take up the excess space and force the filter against the furnace. At some point one might expect the furnace ductwork folks to reduce the size of the filter opening to fit the 3/4" filters instead of 1"". They haven't sold true 1" filters in many moons.

I made sure I got a 4 inch filter housing installed when I had my furnace replaced. 16x25x4 and run a MERV 11. The 4 inch depth adds a ton of filter media and I change it every 6 months. I do like that filter lock product for sure. I don't need it, but it's cheaper then replacing the duct work.

With older systems the merv 8+ filters can burn up your ac system because of the lack of airflow, especially if you only have one air return. It is best to stick with a lower merv rating for better airflow.

These and all the EHR videos here are so informative and well-done that I even watch the ones I'm not interested in :)

I use the less expensive filter but treat it with some spray endust, that or if available with some static spray that way I leave the ar flow unrestricted and also trap more dirt/dust particles.

The magnetic seal is a great idea. However, if you are cheap you can use aluminum duct tape or if you don't want to buy that you can use the ever popular duct tape. Throw it away and replace it when you change the filter.

So funny watching this video. I just bought 2 of these 4 weeks ago for my daughter and son’s houses. They have been working equally as well for them. Previously I used painters tape on them. Luckily my own furnace came with a filter door. Mine is also 4”’s thick and filters better and for a longer period of time. While the filter is more expensive I can double or triple the lifespan.

again, great info. as always

I guess every HVAC installer does this differently but this is the first time I have seen a filter with out a cover over it. Where I am, the filters are retained with in a door or cover to prevent leakage.

Hi I live in TX where we have Heat Pumps, which I am sure I do not have to explain. My house if fairly new less then 6 years old. The furnace has a 4" filter which I change out every 6 months. You taught me something today that I wish was marked on the furnaces which way the arrow on the filter points. After seeing this part of the video I ran upstairs to check my furnace but thank my higher power I had going in the right direction. I wish there was some more information about the Merv standards, I understand the increase in the numbering system and you explain it very well thanks. So should we check with the furnace manufactor to see what is recommended for there systems as far as the merv number should be??? Thanks again I do learn a lot from your videos you provide a great service..

I just found out one of the HVAC techs I had out MONTHS ago installed my heavy duty filter BACKWARD... and it's been one of the hottest summers ever. What a joke. Hope my system is okay. Finally fixed that issue, hoping it will now run a lot better! Lucky nothing broke, from what I can tell, but that could not have been good. Aprilaire 510 filter too...

Great video, thanks for posting. I was changing my 1-inch wide filters every quarter. But when I changed over to the 2-inch wide filters, I was noticing there was no appreciable debris accumulation on them after 3 months... go figure. So now they get changed bi-annually instead. Also, I stick with Merv 8. Less resistance than Merv 12. It seems inefficient to use your heater/ AC unit as an air purifier. A stand-alone unit would be a much better solution for indoor air pollution.

We have a return vent near the floor with two dogs in the house in a dusty environment. I check it weekly and replace it an average of every three weeks, but sometimes it only lasts a week - dust and hair.

genius! Thanks!

I use a strip of duct tape, completely seals, you use like 8 ft worth a year and a roll lasts years.. super cheap. Have my house 20 yrs now and I'm still on the first $2 roll lol

Sealing the outside gap doesn't stop your dust from going around a loose filter inside. I used 1/4 inch foam weather stripping at sides of filter inside. It's tight now.

Have worked in the hvac industry many years. I am not a fan of high end 1 inch filters. They don’t address the duct size issues that are prevalent in modern day construction. If your return duct size is just adequate a 3m 13 merv may cause airflow issues that can lead to overheating the heat exchanger or freezing your evaporator coil. The middle of the road pleated filter in the video is good. Remember you can’t change a filter too often. I recommend changing your 1 inch filter every month in the seasons your system is running regularly. Consider a filter upgrade the next time you need a new system. A good filter is worth its weight in gold. Some of the other system purifications gimmicks I can live without.

Thank you.

Awesome. Thanks

I don't think that poll question was worded right. For example, a person who replaces his filter every 6 months might have recently replaced it when he said he last replaced it less than 3 months ago. The correct question should ask how often you replace the filter, not how long it's been since you last replaced it.

Thanks for the info, Go Illini!

That is really a great way to fix the opening. I use two filters to my A/C. One at the air handler which is 5-1/2” thick that I change once a year and the other normal 1” where the air intakes inside the house that I change ones every 3 months. The question is that over kill and would that effect the air flow in the house. Great video as always.

Great tip I have this exact setup

Finally, a straight answer with a great explanation! Seriously, after years of wondering and worrying about this I now get it thanks to your video. I have the same system with the same issues. I use Filtrete 1900 with MERV 13 it makes a big difference. There is much to consider, pets, carpeting, vacuuming, moving furniture and odd jobs being done around home all make a difference in the air quality. Thank you again for this well done video!

I guess I am fortunate. When we upgraded our HVAC system 35 yrs ago, we had an electronic air cleaner added to the system. It still works very well even after two system upgrades.

If you use a high Merv rated filter it will reduce more than you know. It will make the blower work harder and reduce the life of the motor. It also reduces the amount of airflow going to the vents. If you want zero air flow and a motor burn out....by all means use this advice. The open slot issue can be fixed by using magnetic register covers cut to size.

ThankYou so very very much…

I used to use those higher $$ filters but found that they lead to premature plenum warping/cracking as the air doesn’t flow nearly as well through the furnace. Put your hand against the ducting above the heat exchanger when the furnace is running… with a high merv filter you’ll find it to be extremely warm.., even hot… move to a merv 8 (or less) and you’ll see how much cooler the plenum is as the air is moving more freely. I also noticed how much better the air moves around my home with a merv 8, no more cool spots, furnace is on less and less condensation on the windows. I’ll preach to anyone about not using filters above merv 8.

I put in a giant return air filter grate, and it holds 20 x 30 filters which i can fit the thick 4- or 5-inch ones in it. the air conditioner normally would have a 1-inch thick 20x 20 so i can have merv 12 and great air flow at same time with long life of filters.

Can a filter installed in the wrong direction cause enough restriction to induce evaporator coil ice buildup?

I only use up to a merv 8 and change them every month, 2 months at the very most. 👍 One of our properties filter becomes a dark grey after a month, used too high a merv value and it damaged the motor by cutting off the flow. A $10 filter cost me $300 motor replacement!

I didn't know there was a spot for a filter at the furnace. Gotta go check mines now.

Ever go through winter without a furnace. I change mine every time my thermostat reminds me. I need to find the manual to verify air flow requirement though. I've been using the magnetic filter covers ever since I found out about them.

I have a Nest thermostat. It will tell me when I need to change my filter based on HVAC usage in hours rather than the 3 months calendar. That way, if your system runs often, you will need to change it more often. However, if you don’t use your system that much, you can wait past the 3 months before changing the filter. The Nest will actually email you your monthly usage, how it compares to previous periods and how it compares to your Nest neighborhood. BTW, my furnace has that metal cover, blocking the filter side opening.

LOL love this setup, all the air can just go in front side and bypass filter. Another big issue I am seeing is zero sealing or checking of leaks. I recently looked at a new install and the return was leaking at every joint, it was a joke. If you don't carry a smoke pen as part of your tool kit shame on you, every installer should be smoke checking post install and then sealing as needed. Time and time again I see people miss the most important step, checking for air leaks, not hard and very important.

With 1" filters, I'd expect way more filter changes are needed per year (4+ possibly). They simply have the least surface area, least filtration and clog much faster. Modern/newer HVAC systems now use filters as wide as 4" that provide much more surface area and better filtration. Many allow much higher MERV rated filters to be used, trapping smaller particles and increasing air purification. I have a MERV 13 rated 4" in my newer HVAC system and have noticed a huge decrease in dust around the house, changing it twice per year. Taping all the duct joints you can, with aluminum backed tape, is also a good thing to do... including the seams at the furnace (you can see some gaps in your video).

Let me give you another piece of advice. A 1" thick filter is completely inadequate for the task, because if you use filtrete it's too restrictive and it's gonna kill your furnace, and if you use fiberglass you're not really protecting your evaporator from getting dirty, so what you need to do is have your HVAC contractor modify that filter slot to accept a minimum of a 2" thick filter, which has a greater filtration area, a lower face velocity, and less restriction to the flow of air. Ultimately this saves you money in operational costs and extends the life of your equipment.

i have just magnetic sheets that are white on one side like refrigerator magnets to cover vents in the winter you can cut it to fit they are about 12 x8 inches you can buy those at Home Depot or Lowes probably work as well as that thing does.

Change the filter by usage and air flow drop rather than by months.

Every HVAC guy I have talked to lately would say no, no, no to anything much over Merv 5. If you need to filter the air that badly... buy an air filtering system don't suffocate your HVAC. The suction from the blower fan really should pull the filter tight to the front of the box. If you have a gap on the furnace side once that blower comes on... then I would suspect that you have a bigger problem at work... bad filter box framing.. or a really bad blower fan. To be honest, as long as you are not pulling excessive warm (during the warmer months) or very dirty air into the system around the box, I think it's pretty much a non-issue. But the filter lock is a nice inexpensive solution to either provide peace of mind and\or solve some issues which might occur in a small amount of scenarios.

K&N makes a washable/reuseable furnace air filter. A 14x30x1 MERV 11 is pricey at $70, but over the long haul, a worth while investment. I bought mine back in 2021 and would have gone through at least 12 disposable filters by this time, so the K&N's already paid for itself . P.S. Keep a disposable filter on hand to use while the K&N filter is drying.

I have been looking for something to keep the asbestos in my mechanical room from entering my HVAC system and circulating throughout the house. This should help.

Looks better with a new camera view

My question is about ventilation I live in a basement suite where the furnace is in a closeted space on our floor. The closet the furnace is in has tons of vent slits on all 4 closet panels. I have a door that opens to a stairwell leading to an unfinished sub-basement. After opening the door, but before you go down the stairs, the wall to the right is unfinished to the furnaces closet room. The sub basement has a very musty smell, air feels heavy to breath, and there's visual (what i'm assuming) mold on quite a few 2x10 floor joists. There was previous water leaks before I moved in I've now learned. I'm concerned of the air quality coming from the sub basement because if we don't keep windows open and hepa units running in our suite, we start suffering allergy-like symptoms. Cough, headache, throat irritation, sneezing, wheezing, chest tightness/itchy, watery eyes, and runny nose. Thank you for the time taken to read. Any insight to my situation is sooo so greatly appreciated. 1. Does the sub basement share air with our basement suite if there's no sign of mechanical exhaust to the outside down there? Could the air down there be affecting us 1 floor up even with the door closed? 2. What are the vents for on the furnace? Do these draw in air and if so, would it pull air up from the sub basement level since the adjoining wall is unfinished? 3. What are the vents for on the closet?