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[August update] Just wanted to add that all my windows have "micro-ventilation" - either by design or simply because they are old and have gaps. So essentially, there is always some air coming in or out in the bedrooms.

So - do I really need those air vents in my bedrooms? Aren't they just a legacy and no longer needed? Please help. Thanks

[End of August update]

My 1950s house has air vents in some bedrooms. They are literally holes in the wall with a plastic grill on both ends.

air vent in the bedroom

I like to regularly ventilate my rooms simply by opening windows. The heating is via a gas boiler downstairs. Yes, there is a log burner in the main living room downstairs, but I use it once in a blue moon.

I would like to completely block off this air vent - basically to fill it in with the expanding foam, plaster and paint over.

The only question - can I safely do it? Any reasons why not to?

Thanks

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  • I am surprised the grills are plastic. I wonder if it is some very fancy plastic like Bakelite. I would expect the grills to be metal. Presumably there are adjustable louvers inside, are there? Could you post a pic of the outside grill?
    – Jim Stewart
    Jul 18 at 14:24
  • When you are ventilating rooms through open windows AND it starts to rain, especially blowing rain, someone has to rush around and close windows. These vents mean the rooms can be ventilated without having to worry about being prepared to close windows in the event of rain. Why would you want to seal them up? Are they conduits for noise?
    – Jim Stewart
    Jul 18 at 17:13

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If the vents are, as you say holes with a plastic grill on both ends, they are for air circulation from room to room, or what is sometimes called a "jump vent" that allows air to be returned to a house circulation fan when a room does not have its own return.

The vents should have no or little effect if you opening a window, unless you are saying you want one room with fresh air and another closed off. If that is the case try replacing the grills with one that is adjustable and closable.

Vents from the interior directly to the exterior, (Through the exterior wall), Are unusual. Can or should you close them off? Are there reasons not to? You will need to consult your local experts regarding home construction and the reasoning for the vents.

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  • Aesthetics is a secondary aspect - my main concern is the loss of heat in winter and draughts.
    – Tom R
    Jul 17 at 12:26
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    So to be correct, You have a vent that goes from inside the home directly to the outside of the home? Where are you in the world? That is highly unusual, however there may be a good reason . You may need to ask local housing the reason for it. Or it is just some quirky thing someone did to their home.
    – RMDman
    Jul 17 at 12:43
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    "Where are you in the world"? England ;-)
    – Tom R
    Jul 17 at 12:52
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    Is this common, to have a vent directly outside?
    – RMDman
    Jul 17 at 13:12
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    Definitely common for properties from mid-20th century. Not so much for modern ones.
    – Tom R
    Jul 17 at 13:27
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Do not permanently block these vents, These allow controlled inflow of outside air into the conditioned interior space. When you turn on bathroom vent fans, a stove vent hood, a vented clothes dryer you are pumping air from inside to outside. This air will be replaced by air from somewhere and you want it to be clean air from outside through a controllable route.

Another pumping route is leaking HVAC ductwork in the attic. Any leakage in the attic is in effect air pumped from inside the living space to outside.

Modern houses have ventilation with energy recovery to replace air pumped from the inside. If no planned route is provided and windows are down then air can be pulled into the living space from the attic or from below in the case of a pier and beam foundation.

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    I do not doubt your answer. I'm just wondering how the air would be clean and from a controlled route if it basically just comes through a hole in the side of the wall?
    – RMDman
    Jul 17 at 22:25
  • You could put filters over the grill or inside the cavity. Without vents like this the air pumped out of the living space will be replaced by air which is dirtier than air directly from outside, namely, air pulled from the attic or from the crawlspace.
    – Jim Stewart
    Jul 17 at 23:09
  • Another thing is when an inward opening outside door is pushed open on entry to a tight house there is a transitory increase in pressure which can rattle a sliding glass door or rattle windows. I would bet there these vents prevent such pulse. Rather than fill these, you should get filter units for them. Just get fiberglass filter material and pack it in loosely so the air has to flow through it but there is little resistance to flow.
    – Jim Stewart
    Jul 17 at 23:16
  • I would expect there to be a copper screen over the opening on the outside. And louvers to shed rain. This seems like something that marks this as an exceptionally well designed and built house. How high are the ceilings 9 ft? 10 ft?
    – Jim Stewart
    Jul 18 at 0:36
  • In the hot parts of the US a quality house of the early to mid 20th cent would have a whole house exhaust fan that would pull air in through slightly open windows. These were called "attic fans" and would pull air from inside the living space into the attic. The attic would be connected to the outside with a large gable end vent. But with these vents you have you would not have to open windows. Better for security.
    – Jim Stewart
    Jul 18 at 0:52

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