Bathroom Extractors

[TheOldFellow]

I'm designing the new bathroom extraction. In the en-suite I did last year I used two Manrose 30w ducted kits, one over the shower (30minutes run) and one over the loo (5 minutes run) both triggered by the appropriate lights (IP65 downlighters with 35w MR16 dichroics, 3-pole isolators etc.,etc..) This has been very successful, but the room is hardly bigger than a large wardrobe.

Now I'm doing the main bathroom, and the shower will be an over-bath job with folding screen. {I'm not interested in the discussion of bath vs. shower vs. separate cubical thanks - too late.} It's a bigger room, but still not very big, and does have two small accessible and open-able windows. I think we need one ducted fan, over the shower-end of the bath to clear the steam, but what extraction rate? Does it need a timer? Humidistats seem very expensive, but should I consider that? Screwfix?

Thanks for any tips. (I've read the wiki)

R.

[Tabby]

A window lockable half an inch open is far more reliable, easier to isntall, lasts a lifetime, makes no noise etc.

NT

[ARWadsworth]

And it lets cold air in.

[Dave Liquorice]

That's what one of the builders said this morning when querying the heat recovery ventilator I'd specified for the new bathroom.

Open windows are fine if you can open them without letting a gale in... The noise of a gale roaring in through a window left in the locked ventilate position is quite something trouble is you loose all the warmth from the room well before it gets too noisy.

[polly filler]

I have a Manrose with built in humidistat, ceiling mounted, above bath, venting out on flexible pipe venting through the soffit. Had no problems and works a treat

[Steve Firth]

TheOldFellow wrote: [snip]

Part of this week's DIY has been the installation of three humidistat extractors. I'd suggest don't buy the fitting kits, which IMO are s**te and have ended up in the bin. Use 150mm stainless stove flue and cut it to length with your favourite angle grinder. You can make a handy cutting surface from two planks. Space them enough apart to give a slot to drop the tube into. Hold the angle grinder steady and rotate the tube to get an accurate cut.

One reason the fitting kits are s**te is that they don't have fly screens.

And tomorrow I'm looking forward to another fun day of drain laying. I've laid 36 metres so far, another 36 to go to reach the septic tank.

[Tabby]

Lockable ajar windows and fans do the same thing, let out foul air and let in exterior air. (Its not possible to extract with a fan without letting air in as well). In an ideal world, the opening would be controlled, with the lock only stopping it opening too far. Perhaps someone will work out how to implement that.

NT

[Dave Liquorice]

Soffits? Don't have soffits, don't have anything that sticks out, it would get blown off. When I said gale I meant gale as in F8 or above, which starts at a tad under 40mph sustained wind speed.

Thinking about it what are these heat exchange ventilators like with back pressure? Pressure that is enough to make fountains of rain several inches high through leaky windows?

[Dave Liquorice]

Well these are top hung windows with restrictors. Left unlocked the wind will blow 'em shut but not quite hard enough onto the seals to stop the draught. And the noise changes from a roar to a whistle. B-)

[Invisible Man]

Half inch open gives thieves opportunity to insert fingers or jemmy.

[Tabby]

-0700 (PDT), Tabby wrote:

Doing so with enough force to defeat the lock twists the window and break the glass.

NT

[ARWadsworth]

let out foul air and

[ARWadsworth]

Well that is not my opinion. Open windows let cold air in.

Well it depends where the new air comes from.

Like a fan with a humidistat or timer then:-)

[Martin Pentreath]

Unless I'm missing something, if your fan vents air to the great outdoors (and why would you be venting damp air anywhere else?) then the new air must come from the great outdoors too. Otherwise you will create a vacuum in your house and suffocate to death.

[Chris J Dixon]

A familiar scenario, not! ;-)

Two words: adventitious ventilation. Unless you have achieved levels of sealing usually seen in "Eco" houses, there will be plenty of leakage.

Chris

[ARWadsworth]

Indeed. The air comes from the rest of the house and adds to other rooms air changes.

My bathroom fan will never clear the steam properly until the shower is off or the bath is empty. However when I open the bathroom door the fan does it's job and clears off all the steam within 10 minutes. That why I use a 10 minute timer on my fan.