What is this vented hole in my wall?

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DuaeGuttae

Minister of Fire
Oct 26, 2016
1,621
Virginia
And is there any reason not to seal it?

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This is on the north side of my house hidden behind the gas meter. It’s beside the garage, but it’s not vented into the garage. It’s a framed opening with a screened vent on the inside that must go under the pictured nook. We have several books and an entertainment center built into a family room wall.

We keep the entertainment center covered by a large tapestry because the previous owners left behind a large television that I didn’t want to be on display all the time. (We use it perhaps twice a year.) It was quite obvious when we first put up the tapestry that we were cutting down on drafts. We’ve always assumed that part of the reason that wall is cold/hot is that it backs onto the unconditioned garage. I’ve been working on air infiltration, though, and know that lots of air comes in the outlets. I’ve gasketed them and use baby proofing (there are at least six outlets in the wall), and that helped. I also sealed outlets and holes up in the garage wall, but only today did I realize that there is an actual, intentional hole right under the whole area.

Why is it there? Is it somehow important for the house? Is there any reason I would not block off this strange thermal anomaly?
 
Around here you see those for some air flow mostly in crawl space or unheated spaces that need to be vented to stop mold and mildew.
 
almost thinking that may have been used for some sort of heat ducting at some point or fresh air inlet for a furnace or something? But if its behind your gas meter its not code.. here a gas meter cannot be located within 3-5 feet of a opening because sometimes they vent off and that gas can enter the home. Of if their is a leak in the meter it will enter the home through the opening. I would get that sealed off so nothing can enter the home from that point
 
is it an intake or exhaust? radon system or fresh air exchange system?
 
Around here you see those for some air flow mostly in crawl space or unheated spaces that need to be vented to stop mold and mildew.


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The house is built on a slab, so there’s no formal crawlspace. The vent opens into the space just under the nook that’s obscured by the recliner. It’s totally hidden from inside and pretty well obscured outside, too. The interior wall is fifteen feet long and approaching three feet deep, but the nooks remove a lot of volume. Would that kind of space between the house and the garage over a slab be prone to mold or mildew? It’s somewhat humid in the summers but nothing like the east coast where I come from, but I almost wonder if letting humid air in would make it worse instead of better.

Given the comments about the possibility of pulling gas in from the meter, we’ll be sealing it, I think. If we had to, though, we could put a vent in a different spot if it really needs it. Any thoughts?
 
almost thinking that may have been used for some sort of heat ducting at some point or fresh air inlet for a furnace or something? But if its behind your gas meter its not code.. here a gas meter cannot be located within 3-5 feet of a opening because sometimes they vent off and that gas can enter the home. Of if their is a leak in the meter it will enter the home through the opening. I would get that sealed off so nothing can enter the home from that point


I wondered if it was supposed to be a garage vent in the original plan but placed one foot too far over. There is another vent on the back wall of the garage that opens to the outside. It’s the same size and construction. This one just doesn’t open to the garage but into the space under our nooks.

Thank you for the information about the gas. I think that clinches sealing it for us. All our HVAC is in the attic spaces (I cringe admitting that, but it’s how things are done down here unfortunately), and they’re vented up there.
 
is it an intake or exhaust? radon system or fresh air exchange system?

Good questions. We don’t have a radon system, and we can’t figure any appliance it would connect to. The only option would be our oven, but that is vented into our kitchen. (I use the grill in the summer extensively as that oven is not allowed on during the heat of the day.) I really do wonder if it was just a misplaced garage “suicide vent,” or if these nooks were somehow built by taking some space from the garage. I was pretty baffled by discovering this.

I appreciate everyone’s insights into this. I’ll be glad for any suggestions about proper sealing. Thank you.
 
My guess is that it is a spec. home that had options that could go on the tv wall. Optional outside air for fire place?
 
I had to look up what a “spec. home” was. Learn something new every day. It is possible that this home was something like that. I also know that earlier owners made some additions, and it’s clear that some of the outlets and wiring on the “nook wall” were done more shoddily than the original construction, so it’s possible that the nooks themselves are additions.

There is a pre-fab fireplace actually on the same wall as this vent, but it has its own dedicated fresh air vent on the chase itself. I really don’t know why this one was originally put it, but it certainly seems to do more harm than good where it is. Right now I have it blocked with plastic. I’ll have to have my husband seal it up properly at some point.
 
Open it up see what is behind it before sealing it it may have some purpose
that you cannot see from the outside
 
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