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Frost King

Model # MC815

Internet # 100345609

Store SKU # 181588

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


Maximum Duct Length 
Maximum Duct Width 
Outside Length 
8 in 
Outside Width (in.) 
15 in 
Color Family 
Grille material 
Product Weight (lb.) 
1.2 lb 
Warranty / Certifications
Manufacturer Warranty 
90 DAYS 


Rated 2.8 out of 5 by 50 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 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 WASTE OF MONEY These magnets can barely even stick to a fridge door. They can't even stick to one another, how are they going to stick to a ceiling vent when the air is on full blast? September 15, 2015
Rated 1.0 out of 5.0 by Doesn't stick when regular magnets do. I would recommend finding your vent in the store to test this product before purchasing. It doesn't hold at all for my vent, while regular magnets do. September 12, 2015
Rated 1.0 out of 5.0 by Don't waste your money. I got these to cut to size and cover the two ceiling heat/ac vents in my basement. Why air condition the basement when I'm only down there to do laundry? Apparently these will not "stick" if your vents are painted. Would have been nice to know this before hand. I ended up cutting to size and then using a lot of electrical tape to make them stay in place. The force of the air is already pushing the tape away. What a waste of money. August 18, 2015
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 not strong enough The magnetic covers stick fine until the a/c comes on... then they go flying off. The magnet is not strong enough to stick with the initial force of the air. We did use two-sided tape which helped, however, I believe that might pull the paint off. August 16, 2015
Rated 5.0 out of 5.0 by Worked Great ! This magnetic vent cover did the job. We closed the air vent with the lever, and the magnetic cover blocked the rest of the air that was coming thru. One thing to keep in mind. The vent has to be metal, and there cannot be too many layers of paint on the vent. So you might have to remove some paint from the vent, if there are too many layers. Too many layers of paint will prevent the magnet from touching the metal. Worked great ! October 24, 2012
  • 2015-10-12T11:53:10.911-05:00
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