I would like to be able to use the vents in my house in a way that targets specific rooms/areas more than others. Sometimes I want to completely close off a room from being temperature-regulated by the furnace or air conditioning.

It seems like most of my vents still let a significant amount of air through when I close them (I would estimate that closing the vent still lets through 20-40% of the air).

Is this intended? Would it be harmful to the furnace blower if I got vents that would seal completely and if I were to close 30-40% of the vents throughout my house in order to target the air in specific rooms?

2 Answers 2


Sealing vents off can damage the duct work and shorten blower life. I have had to open walls where the owner closed a couple of bedroom vents this caused the main duct to split inside a wall I would not totally seal it off it may not sound like much but the main duct has a large area and the flex lines can break loose or metal trunk lines can split I have seen both.


This would very likely be okay.

Instead of permanently sealing these vents, there are reversible, commercial solutions. I'm not sure if we can link products here, but search for either magnetic vent covers or rubber vent covers.

  • I wouldn't permanently seal them. If it's something that would be ok, I would start by looking for vents that seal completely. I've seen the vent covers before but to my knowledge those are meant just for return-air vents. By the way, do you have professional experience or source to back up the idea that it wouldn't be harmful to the central air system? Jul 16, 2018 at 13:09

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.