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Kitchen ventilation - both hydrostatic fan and cooker hood?

Postby xzenner » Mon Jan 25, 2021 2:15 pm

Hi Everyone, DIY newbie, thanks for having me!

My house is heated via LPG, so its super expensive to heat, meaning I'm constantly battling between stopping air escaping and getting rid of moisture and only heat the rooms I'm in, so kitchen and bathroom are usually cold and hard to keep mould free.

I've read the ideally houses should use extractor cooker hoods over recirculation, this sounds ideal as I want the steam out of my house.
but my concern is that it will also "pump" out warm air.
I also have got a wall ventilation fan in the kitchen, and was wondering if there is a need for both if i install an extractor hood or if i can brick up the wall fan hole, and just use the extractor when cooking.

or is there a way to have the wall fan routed to the extraction ducting?

Thanks very much.
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Postby stoneyboy » Tue Jan 26, 2021 10:22 pm

Hi xzenner
Fit an extractor hood and only use it when cooking, this will then get rid of the steam.
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Postby ericmark » Wed Jan 27, 2021 9:27 pm

The heat recovery unit comes in two basic types, with heat exchanger in a box, or with heat exchanger built into the pipe which goes through the wall. But you are looking at £250 plus.

So the other method is a heater which vents combustion gases outside.

There are regulations on the efficiency of heaters fixed to a building, so be it gas or oil the units tend to be expensive. I am assuming when you say LPG your talking about a little portable unit, which don't tend to have a flue, and these were years ago fitted in caravans and were a problem if used a lot, as caravan got wet inside, but then we got the flue through the floor unit, with narrow boats we got oil powered units very compact.

[attachment=0]Oil-heater.jpg[/attachment] Kits like this are not in theory permitted for a building as they don't comply with efficiency required. It is also 12 volt powered so it would need a power supply, but costs less than £50.

Main point is it has a piped flue so combustion products are not released into the home.

Clearly best is a problem gas or oil boiler, cheapest boiler around £500, but still needs radiators etc.

Working abroad I have made all sorts of heaters, using all sorts from old engine oil to wood, but these were in building where we did not sleep, with more than one person, so very little danger of gassing us, in the home it needs to be safe, and building regulations come as parts.
Part F ventilation plus Part J and Part L all down to heating and ventilation we have rules like

"c. a gas fire, other space heater or gas water heater of up to 14kW (gross) heat input (12.7kW (net) heat input) must not be installed in a room used or intended to be used as sleeping accommodation unless it is room sealed or equipped with a device designed to shut down the appliance before there is a build-up of a dangerous quantity of the products of combustion in the room concerned."

I think gas heater need to be 89.5% or better efficiency and the cheap units fitted in boats or caravans don't comply. Also there is a requirement for the installer to be trained with a building, but not with a caravan or boat, so in real terms you should be using electric. Or have a proper system installed.
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