Warm air vents from chimney regulations help.

[AndyP]

How would this be regulated in the UK?

This is our wood burner. Smoke goes up through a flue. There are two vents in the living room chimney breast to allow warm air movement.


In the room behind the chimney breast is another vent. This room was an office when we bought the house and is now by eldest’s bedroom. Room size 4x3x2.5m = 30m3


The two windows in the bedroom each have trickle vents rated at 15m3/hr


At the other of the room is this vent to a downstairs loo and shower room


This is the vent on the other side of the bedroom wall in the shower room


And the vent in the shower room to the extractor (permanently on) in the loft.


My daughter rightly complains about the noise that emanates from the vent into the shower room so I was wondering if I could block it up?
I am struggling to find what, if any, regulations there are about warm air vents from the chimney into bedrooms and any required fresh air circulation requirements. How would this be viewed in the UK?

We do have smoke detectors in the hall outside the bedroom and a carbon monoxide detector in the living room on the mantle piece.

 

[Rod]

I've never come across that arrangement in the UK. All the old houses I've lived in had fireplaces in most bedrooms but often blocked up.

Mikes your man I guess?

Rod

 

[RogerS]

For the heat to come from the chimney vent and into the bedroom requires negative air pressure which is currently provided by the permanently on extractor in the bathroom. If you seal up the vent between the bedroom and the bathroom then I reckon you will not see much heat getting into the bedroom.

If there are no trickle vents in the bathroom then it's going to get very steamy since the air supply comes from the bedroom. Not to mention smelly!! How good is the seal round the door to the bathroom and does the other side get access to fresh air?

Try it out.

 

[Mike G]

.......Mikes your man I guess?.......

I'm struggling. What's a "warm air vent" in a chimney? Why would you ventilate the space between a flue and the original chimney? Rhetorical questions......this is me thinking out loud.

OK, voids should either be ventilated, or filled, hence the vents. Now, these vents aren't supplying fresh air to the room, they are supplying fresh air to the void in the chimney, from the room, and the term "warm air vent" is just misleading. The fresh air requirement for the room is met by the trickle vents. So, from the room's point of view, the vent's are superfluous. The remaining question is does the chimney need venting to such an extent that losing the vent in the bedroom or shower room is a problem? Well, in the UK, one vent at the bottom at and one at the top of the stack is all that is deemed necessary (I doubt there is any regulation on this.........it's probably just accepted as good practise).

My view would be that you can block up the vents you don't want so long as you retain one near the bottom of the stack, and another near the top. Better still, block them all up, get up on the roof with a few big bags of Vermiculite, and fill the entire void around the flue. Given that most of the time a chimney is losing heat from the house to the outside, this is always a good idea, even if it reduces a little the amount of heat you get from the flue into the house when the fire is on.

Did I get anything wrong?

 

[Mike G]

Roger's post crossed with mine.....

So Roger (and Andy)......are you assuming these vents are a source of heat for the rooms? Because, as Roger said, without actually drawing the air out from around the flue, I can't see that this would work. I'll take a little guess that any warming would be very marginal indeed. I'd still be inclined to block up the vents and insulate the stack.

 

[AndyP]

For the heat to come from the chimney vent and into the bedroom requires negative air pressure which is currently provided by the permanently on extractor in the bathroom. If you seal up the vent between the bedroom and the bathroom then I reckon you will not see much heat getting into the bedroom.

I've taken some temperature readings on the vent in the bedroom tonight. Tomorrow I will block up the vent with some compressed insulation foam and tape and take measure again.

If there are no trickle vents in the bathroom then it's going to get very steamy since the air supply comes from the bedroom. Not to mention smelly!! How good is the seal round the door to the bathroom and does the other side get access to fresh air?
Try it out.

There is a 3/4" gap under the door to he shower room and bedroom. With the vents blocked up I will try and gauge how mush extra "steam" there is after a shower on Sunday.

 

[AndyP]

Roger's post crossed with mine.....

So Roger (and Andy)......are you assuming these vents are a source of heat for the rooms? Because, as Roger said, without actually drawing the air out from around the flue, I can't see that this would work. I'll take a little guess that any warming would be very marginal indeed. I'd still be inclined to block up the vents and insulate the stack.

Here are some photos I have just taken.

1) The "warm air vent" in the chimney breast in the living room. Holding it up there my hand was getting both tired and hot so it is probably not showing max temperature.


2) The "warm air vent" in the bedroom where I could hang the thermometer for 5 mins.


Sorry about the -68.8 outside temperature. The sensor is broken. But the inside temperature I can assure is accurate.

So undoubtedly warm air is being drawn out of the space between flue and the chimney breast.

If I could get up on the roof and tip a bag of Vermiculite it would all end up on the living room floor.
This image is looking up above the top of the stove. The shiny steel flue can just be seen


I am not at all sure if this is the "norm" here as I do not know anyone who has a similar set up.

 

[Mike G]

Impressive.....

Is that the only heat source for those two rooms?

 

[AndyP]

Impressive.....

Is that the only heat source for those two rooms?

No all rooms have electric convector radiators. But these are only used if we are away and can't light the fire. A timer will switch them on as required. In the depths of winter the stove can be kept alight overnight with the careful selection and timing of the last log and regulating the air intakes to the stove (there are two of those). What I would dearly like to do (but I lack the courage) is make a hole in the transom above the double doors that lead from living room to the hallway. Said hole would be about 2 feet to the left of that warm air vent. With a small computer type fan in the hole I reckon I could improve the warm air flow around the house considerably.

The house has solid concrete block and beam floors and the heat from the stove/chimney will slowly warm up the upstairs floors which will stay warm for most of the following day even if the fire is not lit. At this time of year I am only lighting the fire at around 5 or 6 pm or even later.

The only room that does not get heated by the fire is the kitchen which has a couple of hours of radiator heat each morning.

We also benefit from an east and south facing aspect in the living room. A sprinkling of sunshine, even on the coldest days, and if the fire is lit than the windows are open to reduce the temperature. Outside walls are concrete blocks with 6" of a compressed foam type insulation. Wooden shutters help keep the heat in at night, we have no curtains anywhere.

 

[Alex]

Quite possible its an inset fire with convection jacket on that has ducting to duct warm air to other rooms. You can get fan assited ones. If installed correctly they are uk compliant. Stovax make one
http://www.stovax.com/stove-fire/riva-w ... s/riva-55/

 

[RogerS]

Quite possible its an inset fire with convection jacket on that has ducting to duct warm air to other rooms. You can get fan assited ones. If installed correctly they are uk compliant. Stovax make one
http://www.stovax.com/stove-fire/riva-w ... s/riva-55/

He does live in France !! :lol:

 

[Alex]

http://www.stovax.com/download/Technica ... ctions.pdf

Thanks Roger.

 

[RogerS]

http://www.stovax.com/download/Technical%20Documents/2.%20Fires/Built%20In%20&%20Wall%20Mounted%20Fires/Wood%20&%20Multi-fuel/Riva%20Multi-fuel%20Cassette/Optional%20Extras/Riva%20Ducting%20Kit%20Installation%20&%20User%20Instructions.pdf

Thanks Roger.

Sorry Alex...wasn't trying to take the Mick...just that the thought of France being sophisticated enough to have that.....tongue in cheek :eusa-whistle: digging hole.....

 

[AndyP]

Thanks Alex. I wish there was ducting as per your link but alas no, just vents direct from the chimney.

I did block the vent between the shower room/loo to the bedroom yesterday.


Foil back compressed foam insulation was used and it was wedged in there tight enough to prevent any light showing through. It does not seem to have any any detrimental affect on the heat output of the warm air vent. With the bedroom door closed it reached the same sort or temperatures equally as rapidly as the night before.

As for the steam in the shower room, this is harder to quantify and measure but after a shower this morning I cannot see any difference. We tend to open the window after the shower anyway and will continue to do so.

The one question that still bugs me is why the vent between the shower room and bedroom was put there in the first place and why no trickle vents in the shower room window? This is probably a rhetorical question that will only be answered by the builder who put them in.

 

[RogerS]

But has the 'mod' satisfied your client ?

 

[AndyP]

Sorry Roger forgot that bit. Yes there is certainly less, even no, noise coming through the blocked vent. The wall is made from white blocks about 4" thick and there is obviously still sound coming through there but it is far less distinct.