The open flue and extractor fans.

[ericmark]

I was rather surprised to see what was regarded as an open flue. I had thought the old open hearth fire was classed as open flue and my totally enclosed fire was not.

However it seems since it draws combustion air from the room it’s still classed as an open flue.

So in my house, my mother house, and father-in-laws house we all have what is classed as open flue fires and in all cases we have extractors of some type and only use the open flue fires on the rare occasion with central heating with balanced flues being main form of heating.

However when we come to sell the house what will this all mean? Will the fires need disabling or the bathroom, kitchen, extractors need isolating and the hole for tumble drier filling in?

A fire in my mothers’ house was condemned and at the time I never questioned if the cooker and bathroom extractors could have affected the tests.

Reading building regulations it is unclear if the restriction is for whole house or individual rooms. My mother has three extractors and we have been doing work to stop drafts so with all three running there could be a reasonable depression in the house.

I remember once being unable to open the door of a coach because all the extractor fans were on and until that sort of thing one does not realise how they all can mount up. Since I consider the fires classed as open flue are there in case we get a power cut and with a power cut no electric fans are running it does not worry me as far as we are concerned but does worry me as far as selling house goes.

 

[kbdiy]

I'm failing to see the connection. Why on earth would any of this affect selling the house. You sell 'as seen' and it's buyer beware, so if they, or their surveyor, don't question it no problem.

Can't see how a couple of poxy little extractors would make any difference. Maybe if it was a big industrial mother of all extractors .....

I don't know how you sleep at night

 

[JohnW2]

I was rather surprised to see what was regarded as an open flue. I had thought the old open hearth fire was classed as open flue and my totally enclosed fire was not. However it seems since it draws combustion air from the room it’s still classed as an open flue.

Yes, I believe that's the official definition - I think the only 'non-open' flue is a 'balanced flue' (i.e. 'room sealed'), which draws air from the outside as well as exhausting the products of combustion to the outside.

So in my house, my mother house, and father-in-laws house we all have what is classed as open flue fires and in all cases we have extractors of some type and only use the open flue fires on the rare occasion with central heating with balanced flues being main form of heating. ... However when we come to sell the house what will this all mean? Will the fires need disabling or the bathroom, kitchen, extractors need isolating and the hole for tumble drier filling in?

I'm sure that your family houses are no different from millions of others out there. Quite apart from the questions of what the relevant Building Regs actually require (e.g. as you say, do they apply to individual rooms or the whole house), AFAIAA there is nothing stopping anyone selling a house if (as probably usually is the case!) there are things within them which are not compliant with current Buildings Regs. IMO, when the time comes, you sell the houses on an 'as is' basis, and leave the buyers (or potential buyers) to worry about such issues if they so wish!

Kind Regards, John

 

[viewer]

Best leave to selling problems until the time comes - the purchaser may wish to remove the flues anyway. You should, however, fit a carbon monoxide detector. Whilst a few people die from CO and solid fuel fires, many more just feel unwell, have a headache, bad dreams (etc) and never make the connection.
Another reason to avoid negative pressure in Flintshire houses is the prevalence of radon.

 

[ericmark]

I do personally think there is a big difference between a gas fire burning efficiently and between two well defined output levels from min to max to a wood burner where it starts from some paper burning to start the fire with a cold flue so it will take ages to reach the 150°C and either below or above that flue temperature is running inefficiently either by not burning the fuel completely producing particular emissions as well as the gases or wasting loads of heat up the flue.

There are wood burners with ducted combustion air from outside now but the only horizontal flues seem to be the rocket stove which is a DIY thing

and the Hughes

which is still in development neither are really balanced flues and even with ducted air once the door is opened to load logs then it must equalise with room air.

Where a house has a solid fuel fire of any sort I would question fitting anything other than a proper heat recovery unit

but with gas I consider there should be safety systems built in. Unlike solid fuel it is easy to auto extinguish a gas fire and with the first gas fire central heating I had there was a flap and if the flue gases did not operate the flap within so many seconds from starting the flame was auto snuffed.

However I see no auto snuffing on the fire I have now.

"viewer" makes a good point and so I wonder instead of extractor fans should we pump air into the house and let it flow out naturally rather than suck air in naturally and blow it out? Although can't see how that would work with a tumble drier.

 

[JohnW2]

"viewer" makes a good point and so I wonder instead of extractor fans should we pump air into the house and let it flow out naturally rather than suck air in naturally and blow it out? Although can't see how that would work with a tumble drier.

I suppose that, if you really wanted to, you could have a tumble trying 'blowing into' (as well as 'sucking from') the inside of the house (hence 'pressure neutral'), and that would even avoid a lot of energy wasted at times when the house needed heating - but that would result in (a) a bit problem of damp air in the house, (b) a lot of unwelcome heat during weather such as we are currently experiencing and (c) undoutedly a lot of microdust/microfluff in the house, despite the dryer's filters!

Cannot the potential problems be minimised simply by having an adequate 'CSA' of ventilation in the rooms/house (although I realise there is a modern tendency in the direction of 'airtight houses!)?? - coupled, as viewer said, with CO detectors 'just to be sure'.

Kind Regards, John

 

[tew1]

There's no problem with naturally vented appliances, as long as there are adequate non-closable air vents in the room they are fitted. Extractor fans in other rooms will not cause the appliance/fire to backdraught, as long as there are air vents open