Within the last year we moved house into a newish build (circa 96).
In the lounge there is a vent grill near the skirting, which corresponds with a matching grill on the outside wall. In the summer we didn't notice it, but now it's getting colder we can feel a massive cold draught being generated by it.
Why do such vents exist? It is to prevent damp problems?
Can we cover it over in the winter? Surely it will send our heating bill through the roof if we don't!
Many thanks
It might be for a gas appliance in the room ? I found a 6 inch sqare whole when I did my kitchen, the buiders had not botherd filling in around a pipe.
I had one cut into the floor when I recently had a gas fire installed.
If there is a gas appliance in the room it might be for ventilation for that, in which case it could be dangerous to block it up. If there is no gas appliance in the room it should be safe to block it up. Air bricks which ventilate the space below wooden floors should not be blocked up otherwise the joists may become damp and then rot.
Hmm. No gas appliance but we have a "real" fireplace with an open chimney. (although have to use smokeless fuel).
Actually that's a point. Do chimneys let out huge amounts of heat too?
That's what it's there for, then.
You are joking, aren't you?
MBQ
Yer'Know .... I'd started to answer that posting , using almost the same words, then; instead of hitting 'SEND' , I hit 'CANCEL' - thinking ;"they must be joking!" :) I suppose such people have the vote?
Erm, nope. I wasn't joking! (Although I admit it does sound a particularly dense question!)
I lived in a house with a fake fireplace for 20 years, and for some reason it just never occured to me that the chimney in our new house was open to the elements.
OK, so I will open myself up to further abuse: Why do we need a vent in the wall, as well as a chimney? How do people stop precious heat escaping up the chimney in the winter? (Presuming we never / rarely have a fire in there)
The chimney is to let smoke/fumes out. The vent is to let fresh air in (so that smoke/fumes don't come into the room and poison you).
They insert some sort of blanking plate. Don't make it too air-tight (you want to keep the chimney ventilated), but reducing the cross section of the chimney will help.
DON'T forget to remove the plate before you light the fire!
No, it's there to allow you to live.
If you cover it, you won't get any more heating bills at all.
They were largely unneccesary in old houses, what with loose fitting doors and window frames that allowed gale force winds through, this coupled with lots of other draughts allowed the fire to perform perfectly well, once pvc came along and insulation, draughtproofing and all manner of other devices to keep fresh air out, people were dropping like flies until someone realised that fires/chimneys need ventilation at both ends.
On 30 Oct 2006 08:29:43 -0800, a particular chimpanzee named "Martin Bonner" randomly hit the keyboard and produced:
Strictly speaking, it's not. The fire would use all the oxygen in the room and would then smoulder until such time as the emergency services discovered the bodies of the occupants and the incoming oxygenated air would restore the fire. There would have to be a blockage, a downdraught, or the flue not drawing properly for the gases to come back into the room. The air inlet is to allow enough replacement air so that the occupants can breathe as well.
On 30 Oct 2006 08:11:03 -0800, a particular chimpanzee named snipped-for-privacy@hotmail.com randomly hit the keyboard and produced:
In traditional houses with open fires, they didn't. They threw more coal on the fire and wore a lot more clothing away from the fire. In modern houses, you either don't have open fires with open flues (instead having your appliance within the room to maximise its useful heat with ventilation close to the appliance), or at least make them carbon-neutral (log-burning stoves).
Your house must have been built to the Regulations in force prior to
1995. It would be nigh-on impossible to get a dwelling with an open chimney to comply with the Building Regulations of 1995, much less todays.
If you mean when they aren't being used to vent fumes, then yes. When doing heatloss calculations for a room, an unused but still open fireplace wastes around 1kW of heat which goes up the chimney.
Aren't you over simplifying just a bit? Does a smoke bomb test always work, or is there sometimes spillage? Besides the proportion of room air which enables combustion, there is a much greater quantity of air which has to be available to be warmed and rise up the chimney carrying the products of combustion.
Houses used to be much more draughty, and the air simply found its way in. Now everything is sealed, proper provision has to be made.
I recall my parents had a pair of telescopic plastic vents which popped up out of the floor near the fire, and drastically reduced the freezing draught under the door.
Chris
I've always had a vague feeling that our open fireplace actually cools the house down when we have a fire, since it sucks more (centrally heated) warm air up the chimney than the heat it chucks into the room.
I keep meaning to drill a vent through to the outside through the back of the fireplace. When I find the round tuit, anyway.
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