Recommended Bathroom Fan

[pippo]

Hi,

We had our bathroom fitted a few months ago and it was fitted with a Deta 4800 extractor fan (220-240,50hz,20w). The trouble is, the fan is useless. It has very poor extraction (85 m3/ph according to spec, however doubt its even that) and it is also constantly allowing lots of cold air back into the room which makes the room freezing. the condensation that is left after each shower is getting unbearable.

So, I would like to change it, The hole in the cavity wall is 100mm and I dont want to have to open it up. It is also run off its own switch outside the room (off the lighting circuit).

What extractor would you recommend that would fit, has far better extraction, does not allow cold air back into the room and can run off the existing light circuit wiring.

Many thanks in advance for any help.

Pippo

 

[Chri5]

I'd try fitting a back draft shutter on the outside before you replace the fan.

Having done a quick check the performance you have from yours is mid to upper levels for a 100mm unit and by the sounds of it it's sited against a facing wind.

A back draft sprung unit allows air out, but prevents it from coming in. Changing to a unit with an over run timer might also improve the units ability to work.

Say your rooms a modest 2m x 2m x 2.50m height = 10 sq m cube.

Yours clears at 85, so if you have a 4 minute shower even with the unit extracting only (rather than being subject to blow back) the room won't clear for 3 minutes after you have showered.

If you want super quick then it's a larger hole and a much bigger unit.

 

[pippo]

thanks for the reply chri5,

It is indeed against a facing wind, and it has a 3 flap type shutter on the external wall side (is that what you mean?), however there is still quite a back draft. Is the fan maybe too weak against the wind?

 

[Taylortwocities]

Does the bathroom door fit really tight? Does the fan speed up with the door open?
A close fitting door will create a low pressure in the room and reduce the effectiveness of the fan.

 

[pippo]

The door has a reasonable gap under it, it doesnt change speed/noise with it open or closed. I have just found this:

http://www.screwfix.com/prods/36062...ia-Centrif250DP-Centrifugal-75W-Bathroom-Fan#

It is bulkier however is suitable for the original diameter and has good extraction rates. It also mentions a backdraft shutter but if it is the same outside 3 flaps thingy as I have it will be equaly as useless as the old one. The wind catches the original shutter and rattles them.

Would that be suitable for the switched wiring thats already there ?