Bathroom Extractor Fan : Power versus Location

haf

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I have a standard 2x2x2m bathroom where the roof overhangs and results in the wall facing side sloping downwards. This, combined with a chimmney, means the only spot i have on the outside wall is at the opposite end to the shower and at 1.5m height. Given that most of my mold/moisture is directly above above teh shower, I'm not sure if this will be any good?
So I'm thinking that I either need to go through the ceiling (but thats got a different set of problems with no easy route to the outside) or go for a very powerful 150mm fan in the 'wrong' position. The 100mm fans only go to around 95cubic meters whereas the 150's go to above 150 cubic meters.
My question is, if the fan is powerful enough, then does that make up for the fact that the bulk of the shower steam is at the opposite end of the room and at a higher level?
 
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My bathroom is bigger than yours. I have fitted a fan diagonally opposite the shower against the ceiling, and it works fine. I chose a centrifugal 100mm fan for its extra oomph, and it clears the room in 20 minutes. I wired it into a sprung "push to make" switch so it only runs for 20 mins, and it works fine like this.

The key is to have an air INLET opposite the fan to get a draw of fresh air across the room. I have accomplished this as the window (which only opens for ventilation) is next to the shower and above the toilet, and opposite the fan so the fan draws air across the room.

It might be worth noting that I had a quote of £50 for a ceramic roof vent tile fitted.
 
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I have a standard 2x2x2m bathroom where the roof overhangs and results in the wall facing side sloping downwards. This, combined with a chimmney, means the only spot i have on the outside wall is at the opposite end to the shower and at 1.5m height. Given that most of my mold/moisture is directly above above teh shower, I'm not sure if this will be any good?
Although long and/or non-straight duct paths are not ideal (and hence tend to require more powerful fans) you perhaps should not assume that the place where you come through the outside wall necessarily has to be the same place as ou locate the fan and/or it's 'intake', particularly if there is an opportunity (e.g. in a cupboard) to conceal 'interior ducting').

Kind Regards, John
 

haf

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Thanks Steve and it sounds like being far from the shower is not neccesarily the issue. The palce i'm thinking off is opposite the door and offset by 0.5m so hopefully that will be ok for air inlet.
hopefully my attempt at drawing a picture makes sense below
height of ceiling in shower area is approx 2.2m but height of fan will be 1.5m due to the sloping roof

-----------------------------------------
shower............window........fan..1
1................................................1
1................................................1
1................................................1
1................................................1
1..................door.......................1
1---------------------------------------1
 
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The palce i'm thinking off is opposite the door and offset by 0.5m so hopefully that will be ok for air inlet. ... height of ceiling in shower area is approx 2.2m but height of fan will be 1.5m due to the sloping roof
The thing to bear in mind is that if the path between the main air inlet and the fan doesn't go at least close to the shower, the fan will tend to just draw air from the inlet straight to the fan without necessarily involving (or removing) much of the damp air high up in the vicinity of the shower.

Kind Regards, John
 
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The thing to bear in mind is that if the path between the main air inlet and the fan doesn't go at least close to the shower, the fan will tend to just draw air from the inlet straight to the fan without necessarily involving (or removing) much of the damp air high up in the vicinity of the shower

My bathroom is a similar size (without the sloping roof).

The council rewired in Dec 2010 and the job included installing fans in the bathroom and kitchen. I've altered the original diagram to show the placement that the contractors put my bathroom fan and its USELESS.

-----------------------------------------
1.................window........Shower..1
1................................................1
1................................................1
Fan.............................................1
1................................................1
1..................door..... ..................1
1---------------------------------------1

It might as well have not been installed. We've had to treat the shower area for mould on at least 5 occasions in the past 3 years and it hasn't got any better since the fan was installed. But at least the council have ticked the "vent fan" box on their check list.

Incidentally I've also had a couple of quotes in the £50-£60 range to have a vent tile placed so that I can fit an above shower vent that will actually draw away the steam and moisture - (but the council wont let me - grrr).

I'm no pro but based on my experiences, if I were you I would look to doing your slightly more problematic through the roof version and actually get the result you want.
 

haf

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Thanks for the feedback daniel/john.

I must admit my concern is also that the steam from shower will continue to simply go up and hit the ceiling rather than find its way out via the fan.

I will get into the loft again and see if I have any alternatives aside from a roof vent tile. The house is pretty old and I really wanted to avoid messing with the roof in case that introduces new problems.
Plus I was hoping to DIY most of the job and climbing on the roof is a bit much.
 

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