Covering over an air vent

[BearsRails]

Hi.

I live in a house that is converted from a hospital originally built in 1840. And converted in around 1998. The old single skined walls are dry-lined.

Behind the radiator in the living room, there is an a really big air vent (around 12" square). Naturally this causes quite a draft, and my heating bill is huge as a result.

Before I cover it over, I wanted to seek advice on why its important. I know ventilation is important for avoiding damp. But The living room has an open fire place, and the double glazed windows are wooden with vents at the top.

Would it be sensible to cover over this vent all year or part of the year? Has anyone got any advice on what to cover it over with? I was thinking I could velcro some heavy fabric over it so that it still breathes a little.

Any advice is much appreciated.

Thanks

 

[Mickymoody]

I would have thought that the vent was to provide air to be expelled from the building, not injected? So therefore, there is a blockage somewhere?

So either the chimney is blocked, or there is no ventilation through the property?

It's like my 2 up 2 down, if I open both my front and back doors at the same time, then due to the pressure difference, one door will slam.

An airvent should suck air from the property, not inject air.

 

[BearsRails]

Thanks Mick.

You are probably right about the vent, and it is definitely working, all the hot air is rushing out of the living room making it quite cold.

The chimney is not blocked however - it will take a real fire, although we have a gas fire in there.

And on the subject of doors, we only have one outer door in the property, so perhaps this is a factor.

So the question is whether or not I can get away with covering it or not. Perhaps I should experiment? What do you think?

 

[Nige F]

Hospital or asylum The rad was obviously added later. Victorian values and institutions decreed that ventilation was next to godliness. low level vents let air in - high level- even ceiling ones let it out - it`s natural air flow . Your gas fire needs ventilation you need a Registered Gas Installer to look @ it and maybe install a modern vent Before you block any existing one

 

[Big Tone]

This reminds me of what people of my mum’s generation used to say about “don’t let the cold in”. There’s no such thing; you are letting hot air out. Anyway...

I’ve heard this complaint before in conversation where a friend of mine suggested using a less direct panel; something angled down or a chute of sorts so that the wind doesn’t come howling through in a straight line.

Not perfect but maybe less wasteful of your energy.

 

[foxhole]

An external baffle may help prevent a gale blowing in or you could reduce it's overall dimensions.

 

[Mickymoody]

Thanks Mick.

You are probably right about the vent, and it is definitely working, all the hot air is rushing out of the living room making it quite cold.

The chimney is not blocked however - it will take a real fire, although we have a gas fire in there.

And on the subject of doors, we only have one outer door in the property, so perhaps this is a factor.

So the question is whether or not I can get away with covering it or not. Perhaps I should experiment? What do you think?

I wouldn't cover an existing vent, as the air isn't being drawn as it should already. As it was designed, with an open fire, that would expell much more volume of air than it is currently doing, so you are absolutely sure, that the current gas fire installed, has enough venting required? Somehow, something seems amiss, and you should install a carbon monoxide detector in there, to be safe, if you are saying that the chimney is clear, and the gas fire is safe..

Just thinking of your safety fella.

 

[BearsRails]

Guys, thanks this is really useful stuff.

@foxhole - I can't put an external baffle on. Its a Grade II listed building, and therefore we are not allowed to make any external modifications. Besides, externally it is mostly a communal area and most of my neighbours retired in the early-1980's, so there would be uproar

@MickMoody - Are you saying that the chimney should be venting sufficient air that the flow through the grill should be negligible? If so, then perhaps my wife is in fact correct (shock horror) when she says we have a birds next in the chimney and this is inhibiting the air flow. Either way, I will take your advice and get a carbon monoxide alarm.

@BigTone - The internal vent already directs either the airflow down (or collects the air from below when it flows it out).

@NigeF - The Asylum part is where my wife lets me sleep, its officially known as the Gaol I had anticipated there would be enough ventilation because the room is so large 20' x 14.5' x 11', but now you point it out, a gas fire will still need extra air.

Guys, this is very useful. What I will do is get a candle tonight below the vent. Verify as NigeF says, that the air is coming in, not going out as this will prove the purpose of the vent. Then turn the fire on and see what effect it has i.e. will it increase the airflow.

Am I correct in assuming that if the air is flowing into the room, and it increases when the fire is turned on, that the vent is necessary for the fire and that everything is normal?? Or could the chimney still be blocked?

Thanks again guys.

 

[Mickymoody]

When I had a new gasfire fitted, the installer used a smokebomb in the flue, and those chuck out plenty of smoke, I'm sure that even the slightest blockage in the chimney would result in the room being overcome in smoke.

On my old car, it wouldn't start in the mornings, and my girl at the time said, logic dictates that if it won't start, therefore the starter is faulty. I changed carbs, dizzy, pipes, coil, plugs, everything....

..until I changed the starter..and it worked perfectly...like I say she's now my ex!

 

[macfudd]

Any gas fire with a rating of over 7kw requires a permanent airvent leading directly to outside air.

Check the Data badge if you can find one,it should be on the bottom plate of the fire and it should tell you the rating.

You say it`s an open fire,which leads me to think the fire you have is a basket/decorative type.These are aften rated in excess of 7kw and therefore would need additional ventillation.They are also hugely inefficient.

The best thing you could do is to call in a Gas Safe Registered Engineer who`s qualified to work on fires(check the reverse of his I.D. card) he will be able to tell you whether the vent can be blocked up or not and he can service the fire(which should be done every year) and check whether a vent is required.