Frost King E/O Magnetic Vent Covers-MC815 - The Home Depot

Frost King

Model # MC815

Internet # 100345609

Store SKU # 181588

E/O Magnetic Vent Covers

Frost King E/O Magnetic Vent Covers

This item has been discontinued.
The Home Depot no longer carries this specific product.

$4.47 / each


Model # MC815

Internet # 100345609

Store SKU # 181588

The Thermwell Magnetic Vent Covers are white and can be cut to size. They block floor, wall and ceiling metal vents. The covers also fit large side vents. They can be painted to match the color of your walls. They help redirect air movement from one room to another.

  • Blocks out air for floor, wall or ceiling metal vents
  • Helps save energy
  • Magnetic
  • Fits large side vents and can be cut to size
  • Requires Hi-Flow Rite-Temp pressure-balancing valve and 3-way transfer valve to complete the package (not included)


Assembled Depth (in.)  .25 in  Assembled Height (in.)  18 in 
Assembled Width (in.)  8.85 in  Maximum Duct Height 
Maximum Duct Width  15.5  Outside Length  8 in 
Outside Width  15 in 
Color  White  Color Family  Whites 
Decorative  Yes  Grille material  Plastic 
Louvered  No  Material  Plastic 
Product Weight (lb.)  1.2 lb  Returnable  90-Day 
Warranty / Certifications
Manufacturer Warranty  90 DAYS 


Rated 3.0 out of 5 by 46 reviewers.
Rated 5.0 out of 5.0 by This product is fine. I cut these covers to fit and they stuck to my ceiling vents just fine. I should mention that I did make little cutouts for the slide (in the closed position) and the mounting screw heads to assure the covers fit flush with the surface of the vent. Turned on the air and they didn't budge. t think many of the complaints in other reviews may have to do with the fact that these covers won't stick to aluminum/plastic vents (nor to stainless refrigerator doors, which aren't magnetic either). It's also possible that some vents just don't have enough solid metal around the louvers to allow the magnet to stick well. I do think making cutouts for the slide and screw heads helped give me a good result. I'm glad I ignored all the bad reviews and decided to give these a try. June 22, 2014
Rated 1.0 out of 5.0 by VERY WEAK MAGNETIC STRENGTH Bought 2 pkgs and they will not adhere to metal wall vents and ceiling vents. May work on floor vents but do not even try on a ceiling vent. I noticted when opening package that magnetic surfaces do not have much holding strength with each other. JUNK DON'T BUY !!!!! February 7, 2015
Rated 1.0 out of 5.0 by Don't waste your money Magnets is very weak! Doesn't stick to a vertical surface and I didn't even try covering up the registers in the ceiling because I knew they wouldn't stay up there without me holding them. I returned these 30min after I bought them. Best advice I can offer...unscrew your HVAC register from the wall and pull it out. Grab a black trash bag, fold it up so it's about 1" wider all the way around the backside of the register and block the vent from the backside. As you push the register back into your vent, the trash bag gets wedged in and creates a pretty good seal. Don't forget to remove these as the seasons change. July 27, 2013
Rated 1.0 out of 5.0 by Not strong hold - Magnet too weak Magnet too weak. It is not suitable for walls or ceiling vent outlets. But I found an alternative use for photos or paintings. I do not recommend it for vent covers. October 21, 2014
Rated 5.0 out of 5.0 by Works great! Works great on my vents. Sticks just fine. I think people complaining that this isn't strong enough have vents that are aluminum or something or they're not flat. Also they're big. Cutting them to the right size is a breeze with a utility knife. October 28, 2014
Rated 4.0 out of 5.0 by IMPORTANT REVIEW!!! Past bad reviews take notice. I read all the bad reviews and still bought these vent blockers. The price was right, a 110 degree day in VA, and two vents that wont close so I stayed positive. I cut one to the size of my vent on my ceiling and it fell to the ground... Used common sense and cleaned the vent to prevent dust and held it back up to the vent and pressed firmly focusing everywhere except where the screws were and lever to open and close. After a few miniutes it is like it formed itself or joined to the metal and 24 hours later it is still up there. Note: the AC was running at the time and I used a bit of scotch tape. 24 hours later scotch tape not holding but magnet still there. Not sure if the tape helped at all. I think I used it just in case. AC and scotch tape dont mix with cold temps. I would have paid a bit more if these were a bit thicker/stronger magnet and whiter color to match better with the walls. End note, patience and common sense. July 7, 2012
Rated 1.0 out of 5.0 by Frost King Magnetic vent covers Bought a package of these yesterday at Home depot and brought them home and tried to apply to my heat vents - yes, they are metal vents and yes, the louvers were closed. . Virtually no adhesion to the vent. Thought I had defective package so I went to a different Home Depot, swapped them out, brought them home and had the same results. These vent covers are supposed to be magnetic and they barely stick to each other. Definitely not a strong enough magnetic attraction to function properly. A waste of time as far as i am concerned. November 29, 2013
Rated 5.0 out of 5.0 by If it does not stick then it isn't ferrous metal. Easy to cut to the needed size and shape. If one is not enough two can be used. It sticks to iron based metal grates very well. You can even snip off a piece or two to place over the open/shut lever slot. A sharp cutting knife can also make a slot or hole in the cover for that lever. I use these over the grate in the basement near the heating and ventilation system where the air wants most to come out and where it is least needed in the summer. September 30, 2014
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