Can I cover a return vent?

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Forum topic by thecarpentershands posted 01-04-2016 02:00 AM 1091 views 0 times favorited 14 replies Add to Favorites Watch
View thecarpentershands's profile


80 posts in 2070 days

01-04-2016 02:00 AM

Topic tags/keywords: question

Hello there, I am building a built-in cabinet and bookshelf. In the room where I am building it there is no forced air heating, just a woodstove. There used to be forced air in the room because it used to be smaller, it was expanded in 1980, the forced air was taken out and woodstove put in. I am putting the cabinet right where the return is and what I am wondering is if I can cover most of or all of the vent. How I’m building the cabinet will cover over half of the vent. Do any of you jocks know anything about HVAC and can help? Thanks folks.

14 replies so far

View johnstoneb's profile


2692 posts in 2046 days

#1 posted 01-04-2016 02:08 AM

It depends whether that is a return for the rest of the house or just that room. If it is just that room you could cover it. If it also serves the rest of the house you will need to leave some access to it.

-- Bruce, Boise, ID

View Rick_M's profile


10823 posts in 2253 days

#2 posted 01-04-2016 02:09 AM

If it’s a working return then you should leave it alone. Do you have other returns?


View paratrooper34's profile


915 posts in 2825 days

#3 posted 01-04-2016 02:22 AM

Since there is no more forced hot air in the room, you may cover the return vent. In fact, you can remove the ductwork and plug it up at the main branch where it comes from.

-- Mike

View DocSavage45's profile


8430 posts in 2715 days

#4 posted 01-04-2016 03:25 AM


It’s not clear whether the forced air system is gone or just eliminated from this room. There needs to be a balance in the forced air system to ensure efficient operation. Without looking at the duct work it’s not an easy answer. Do you have overhead fans in the room with the woodstove? Air flow is important.

New systems have at least one return per room.

Hope that helps, but your building inspector is very happy to assist the do it yourself homeowner.

Good luck!

-- Cau Haus Designs, Thomas J. Tieffenbacher

View a1Jim's profile


116807 posts in 3450 days

#5 posted 01-04-2016 03:54 AM

If in doubt vacuum off the dust in the existing vent then drill some good size holes in the back board of the toe kick and place a vent across the front this will allow the return to still work

-- Custom furniture

View MrUnix's profile


6192 posts in 2072 days

#6 posted 01-04-2016 04:14 AM

New systems have at least one return per room.

Not entirely true, and depends greatly upon the design of both the HVAC system and building. I used to design and draw up the mechanical blueprints for a largish HVAC company, for both new and existing structures. Every one was different. In the absence of further information, Jim’s suggestion is the most appropriate thus far.


-- Brad in FL - In Dog I trust... everything else is questionable

View Rick_M's profile


10823 posts in 2253 days

#7 posted 01-04-2016 08:06 AM

From experience, if you close off a working return, the room will become dustier. A lot dustier.


View Jim Finn's profile

Jim Finn

2595 posts in 2795 days

#8 posted 01-04-2016 12:56 PM

I am a retired HVAC contractor. You can close it off if there are other return air grills in the house. Most likely there are. I have seen many houses with only one return grill though. Ideally there would be one in most rooms.

-- No PHD, but I have a GED and my DD 214

View thecarpentershands's profile


80 posts in 2070 days

#9 posted 01-04-2016 01:16 PM

Thank you all for your comments. There still is forced air in the house just not in this room. The return does work, it sucks cold air when the heat is on. There are no other returns in this room but there are 4 more throughout the house. The house is about 1,600 Sq. Ft.

View johnstoneb's profile


2692 posts in 2046 days

#10 posted 01-04-2016 01:21 PM

You should leave some access for air flow.

-- Bruce, Boise, ID

View verdesardog's profile


153 posts in 2484 days

#11 posted 01-04-2016 04:39 PM

I would just make some cut outs in the toe kick for air flow….

-- .. heyoka ..

View MNgary's profile


296 posts in 2290 days

#12 posted 01-05-2016 06:12 AM

Where does the makeup air come from when this return is drawing air from the room? I ask because I wonder if heated air from the rest of the house is being drawn into the room. If so, you may want to remove the cover and see if the return opening could be moved higher on the wall and above your project. If the negative pressure in the room created by the return is helping heat the room, I wouldn’t even think about doing something that may reduce unobstructed access to the entire return’s surface.

-- I dream of the world where a duck can cross the road and no one asks why.

View thecarpentershands's profile


80 posts in 2070 days

#13 posted 01-05-2016 02:20 PM

I have decided to do what a few of you have said, and extend the vent out to the toe kick. I will drill some large holes in the back and front and create a channel for the air to go. I will be posting this as a project when I am done. I appreciate all your comments, thanks!

View AZWoody's profile (online now)


1194 posts in 1097 days

#14 posted 01-05-2016 03:09 PM

Where I live, in Arizona, we use AC and do not have any kind of return vents in any room. Only one main return in a central location usually.

To have proper airflow from room to room, the doors usually have a 1/2 gap at the bottom to allow the air to circulate. That’s in older houses and new houses as well.

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