Bathroom extractor fan - advice needed!

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Hi!

In desperate need of an extractor fan for our bathroom and would hugely appreciate some advice in which one to get and where best to position it for maximum efficiency.

As the walls by the shower are all tilled I thought maybe mounting in the ceiling, directly above the shower and ducting into the attic above and out the wall – but am I losing efficiency by skirting the hassle of mounting on the wall? If I went into the attic would I have to use a centrifugal fan because of the length of ducting (2 or 3m)?

As I said, im just after efficiency so any advice on the below would be most appreciated…

Mount on the wall/ceiling/window ?
Which wall/where on ceiling ?
Type of fan - Axial/centrifugal/ones that mount in the ceiling but the fan sits in the attic (I guess these would be quieter?)

Direct links to any suggestions would be great, iv mainly been looking at Vent-Axia and Xpelair. Not fussed about humidity sensors id rather just control manually. Id rather pay a little bit more and know it’s going to do good job (£100 - £150) than waste money getting the electrician to fit a useless fan !

Thank you in advance !
 
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Centrifugal inline fan mounted in the loft, such as http://www.screwfix.com/prods/41379/
Intake grille in the ceiling near the corner furthest from the door (bottom left of your diagram)
Outlet grille in the soffit.
Cut a 10mm strip off the bottom of the door so that air can enter the room.
 
That’s great guys, thank you. Should be able to vent out through the soffit ok.

Why would you not position directly above the shower? Would it be genuinely more effective positioning it in the bottom left of the picture, or is it because it’s not ‘low voltage’ enough to go in ‘zone 1’ above the shower?
 
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Direct links to any suggestions would be great, iv mainly been looking at Vent-Axia and Xpelair. Not fussed about humidity sensors id rather just control manually. Id rather pay a little bit more and know it’s going to do good job (£100 - £150) than waste money getting the electrician to fit a useless fan !

You will be better off discussing the type and location of the fan with your electrician - he will have a better understanding of your needs once he has scoped out the possible runs available to you after taking into account the bathroom zones and the different types of extractor fans available - He can also take care of the Building Control issues.
 
Direct links to any suggestions would be great, iv mainly been looking at Vent-Axia and Xpelair. Not fussed about humidity sensors id rather just control manually. Id rather pay a little bit more and know it’s going to do good job (£100 - £150) than waste money getting the electrician to fit a useless fan !

You will be better off discussing the type and location of the fan with your electrician - he will have a better understanding of your needs once he has scoped out the possible runs available to you after taking into account the bathroom zones and the different types of extractor fans available - He can also take care of the Building Control issues.


The electrician is a friend. He’s been over and said with the loft hatch in the bathroom it’s a simple enough job to run from the light or have a new independent switch.

He’s given me his copy of the Denmans Connector and told me to let him know once iv chosen which one – top guy, just not so good with advise !
 
Why would you not position directly above the shower?
If above the shower, air will flow from the door to the shower, leaving most of the air in the room exactly as it is.

The idea is to position the extractor inlet as far from the inlet (the door) as possible to ensure proper circulation of air in the entire room.

There are no BC issues either, installing a fan in a loft is not notifiable, and as for ventilation - even the most feeble extractor will easily exceed the recommendations for air changes.
 
If it has a separate switch just for the fan.
Most would be connected to the lighting circuit and therefore the existing light switch would be used, and a 3 pole isolator located outside of the bathroom, or in the loft with the fan.

(Bathroom extractors with separate switches are usually never switched on).
 
If it has a separate switch just for the fan.
Most would be connected to the lighting circuit and therefore the existing light switch would be used, and a 3 pole isolator located outside of the bathroom, or in the loft with the fan.

(Bathroom extractors with separate switches are usually never switched on).

Dont forget about the dual pole fcu with 3Amp fuse?
 
Why would you not position directly above the shower?
If above the shower, air will flow from the door to the shower, leaving most of the air in the room exactly as it is.

The idea is to position the extractor inlet as far from the inlet (the door) as possible to ensure proper circulation of air in the entire room.

There are no BC issues either, installing a fan in a loft is not notifiable, and as for ventilation - even the most feeble extractor will easily exceed the recommendations for air changes.


Furthest from the door it is then.

Following from your original Manrose suggestion im torn between the 4” Manrose MAN100 http://www.screwfix.com/prods/98482/Heating-and-Ventilation/Extractor-Fans/In-Line-Centrifugal-Fan-4

Or the 6 “ Manrose MAN150 http://www.screwfix.com/prods/63459...or-Fans/Manrose-150mm-In-Line-Centrifugal-Fan

Looking at the complete range here http://www.screwfix.com/sfd/i/cat/pdfs/20/p4768520.pdf there appears to be one in between, a 5” MAN125 but annoyingly isn’t on screwfix

Is the 4” clearing 180m3/hr more than suffice for my size bathroom, or should I go all out and get the 6” clearing a whopping 430m3/hr, or do I try and find the much quieter (just 38dBA) 5” which clears 220m3/hr somewhere else??
 
Is the 4” clearing 180m3/hr more than suffice for my size bathroom
More than enough. Your bathroom is around 18 cubic metres, so that would equate to 10 air changes per hour, far more than is required.
More powerful extractors are intended for use where the ducting is longer, as the performance will be reduced with long ducts.

Extractors can be too large - consider that in the winter, it will extract warm air from the room as well as the moisture.
 
And talking of warm moist air being blown down 2-3m of ducting in a cold loft - don't forget to install a condensation trap....
 

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