Customer Reviews for FilterLock Air Filter Slot/Door Cover for 1 in. Air Filter

This simple device stops air from bypassing the filters purpose. This two part plastic with magnets allows the areas around the edges of a filter holder to seal out air infiltration behind or around the edges of the filter holder slot. Of course, the effectiveness of the seal depends on the type of slot you system has. My vertical slot unit is not the ideal style for this device, but it does provide some protection. My other unit has a horizontal door covering two horizontal filters. This installation with the Slot/Door cover is ideal and is a perfect seal. The two part cover is excellent here. I will buy a second one so both units have a filter slot/door cover.

This is used to cover over the slot where the furnace filter goes into to the furnace to stop drawing in dust and other stuff when the furnace is on. It has magnets built in so that it will attach to the filter surround. If you look at my photographs you will see that where my filter goes in to the furnace it is not a very easy place to put the FilterLock but I managed to adjust it to fit. This is a handy device that I didn’t know existed until recently.

The opening for our filter is a little bigger than the filter itself and I've always had it covered with a piece of duct tape because our house is pretty dusty and I don't want any air bypassing the filter without getting "strained". That works fine but I have to replace it every month when I change the filter. This cover is a nice gauge vinyl and has magnets that hold it in place. It's a 2 piece cover so one side laps over the other, The magnets hold it in place very well and it's easy to take off and put back on.

My HVAC unit is very near my cats' litter boxes. Not by choice. But I have dust problems from the clay litter and allergy/irritant issues that affect my sinuses, as well as my cats'. I recently have been trying to find the most effective filters and ways to minimize the irritants in my home. I change filters monthly, even if they are 90 day filters because I have to run my interior fan 24/7 to keep temps consistent on all 3 of my floors. It saves me money on heating but causes other problems such as dryness that magnifies irritants like this. These FilterLocks are really easy to place and adjust until you see the most suction. There are 2 strips and both have magnets on 3 of the 4 sides. I would give it an "Excellent" but my filter door seems to be sealed fairly well, so I can't see the full effect. I would love have a better filter system altogether, but its good to know one source of the problem has been addressed.

I never thought about how much air escapes and/or enters the gap opening where my furnace filter is until I saw "FilterLock" on the Home Depot website. It really makes sense to close these openings. With 3 dogs, I need as much clean air from the blowers circulating in my home as possible and FilterLock is definitely helping because before I attached the FilterLock I felt the air blowing out from the slot opening. Dusty air was probably being sucked into the furnace as well. The FilterLock comes with two 14 1/4" x 4 1/2" plastic strips that contain fairly strong magnets all around them except for along the bottom. Now I need to order another set to put on the other side of the furnace filter slot opening. I believe having the slot openings covered, it should help my furnace filter function better also.

This is one of those things everyone should get. Every time I change the filter I notice dust on both sides of it . Because it's not a tight fit in the slot, outside unfiltered (and unheated/cooled) air is getting sucked in. This is such a simple and universal solution that it should just come with furnaces. It's basically a shower curtain liner. Two pieces of thick plastic and magnets. Put one on, put the other over it so they overlap, and that's it, and it's reusable so there's no need to buy a new one every month. No more air getting in, no more air getting blown past the filter. Better dust filtering and better efficiency for your system.

I used this to seal up my filter slot opening to prevent particles from not being filtered through my HVAC system. I was a little worried about it as first because I thought it used adhesive but it is magnetized instead. Installing it is pretty easy. The problem I had is that I cannot fold it over the top of my intake manifold. (see picture) I had to slide it down a little which may lead to some leaks. I have a 16" tall filter and the cover was easy to manipulate over that spot. The package says it is for 1" filters but I imagine it can cover larger ones. The material is latex-like and the seal is pretty good although not air-tight. Make sure you install it nice and taught. My favorite feature is that the seal is re-usable.

Prior to installing the cover, I had the filter opening covered up with painters tape, which leaked a little bit of air and caused the air handler to make an annoying whistling noise. The FilterLock seals much better as the suction pulls in the plastic. The whistling noise is gone and less air makes it around the filter. Installation was straightforward - just place it over the opening and line up the magnets however you can. It can be cut to fit (even through the magnets), but I left it as is to provide more overlap. The magnets themselves are decent - their grip is OK. I guess its a trade off as stronger magnets wouldn't even be slightly flexible and can't be cut.

I had the opportunity to evaluate this Filterlock cover. So simple an idea that works so well. Personally, I had a whistling filter from air leakage at the filter instal opening. Not many furnace filter plenums come with a cover anymore. I installed this item in 2 minutes. It is held in place with strip magnets and adjustable to your needs very easily. Note that it even wraps around the corners for a great seal. Photos are of my instal. Now I know all air is passing through the filter and I'm sure my airborn contaminants will be reduced.

I waited for 2 filter changes before writing this review. Though it's hard to compare a dirty filter to a dirty filter to measure a difference. This is a PVC material with magnets on the sides that help hold the product in place. it comes in 2 pieces however one of the top edges does not have magnets which seems strange and limits the amount of self adhesion this edge would have. However it seems to work well. But then again not every filter slot on a HVAC unit is created equal. My unit uses a 1" filter, however the opening is at least 3" with a door that slides into place. So if this is something like your set up I would suggest using the FilterLock along with the existing door to help make the system as air tight as possible. I would only suggest to look at your filter door and see if this product makes sense or if you need a bigger size.

This sealed the large opening that my furnace filter slides into. My furnace filter opening is oversized and misshapen because of the way it was installed. The furnace filter is only one inch wide and the opening is at least 3 inches wide. This covered the opening and sealed it. The product is 2 blue flexible plastic sheets with magnets on three of the four sides of each sheet. One sheet goes on the top of the opening and the other goes on the bottom, overlapping the top opening. The magnet hold the sheets in place by gripping to the sheet metal of the furnace. The magnets can be bent so they can grip at a corner. I really expected the cover to be sucked into the furnace, but to my surprise the magnets held them in place well and sealed the opening.

High quality product; heavy vinyl and strong magnets. Should be effective for most furnaces with 14 inch filters, ineffective for mine due to filter size and configuration of the filter box (ductwork that holds the filter). My furnace uses 16x25 inch filters in an unusual filter box so the cover left gaps at the top and bottom of the filter (see photos).

As shown in picture 1 the product comes as 2 pieces. As you can see in the photo 2 my installation was not a simple slot as depicted on the products packaging. The filter slot cover can be cut in half to improve the fit. Space has been left between the magnets to cut them as shown in photo 3 With careful placement I was able to cover my filter slot as shown in photo 4. I believe the product could be improved by making the magnets stronger. I had difficulty getting the lower section of magnets to stay stuck on the furnace duct.

Rating provided by a verified purchaser

Does a very good job of covering the HVAC filter slot.

Works great. They should be made to cut to size as they are short and it took two to cover my 24” vent.

Good concept, but it didn’t fit my air con.

The magnets did stick to the furnace but the magnets did not stick to the duct work. And the duct work was clean.

I was planning on using sheet metal to enclose my furnace filter slot but this does a great job. I wished that I would have had these when I was finishing my basement. It would have eliminated a lot of dust migration throughout the house.

It did not stick very well. Magnets are weak. They are Basically thin magnet strips inside plastic covers. If I slowly put it on the unit, it kind of sticks. But, I am not sure if it would stay if there is some vibration on the unit. You can probably use a similar piece of plastic with some strong magnets on it. I am returning mine.

I'm trying to reduce the amount of dust getting into the furnace and this has secured the area around the filter. The configuration of the cover is flexible to fit and seal a variety of filter slots. It is reusable. I gave one to my mother, have one in my rental property and I am purchasing another for my personal property.

Works great!

Worked great

The opening where my filter slides in, was wide open. I installed the cover and it worked great to seal the opening.

It’s perfect! Easy to put on and take off when you need to change the filter and it saves energy by covering the vent slot once it’s in position. It’s exactly what we were looking for! Thank you!

worked perfectly, passed county inspection

Fit the area perfectly. Installed in less than 5 minutes. Just what was needed to close open space around filter.

Nice product, easy to attach, built-in magnetic strips, seals air filter

Rating provided by a verified purchaser

Rating provided by a verified purchaser