Bathroom extractor selection help...

[MattChan]

Chaps

My bathroom is 2.1m x 2.7m x 2.3m and has a bath and a shower cubicle.

Using the fan selector on TLC direct I get a fan requirement of 65.2l/s. To meet this I have been looking at the S&P 4" 250m3/h TD Silent fan https://www.tlc-direct.co.uk/Products/SLTD250SILENT.html

This will run though 4" rigid ducting to a cowled vent though about 3 elbows over the total 3m length of the run, one as it comes out of the ceiling then one to go down and another to go out through the wall.

For a relatively small additional cost it would seem I could go up to a 5" fan and 5" duct work. My thoughts were that I could throttle the larger fan back to a lower speed setting and achieve roughly the same extraction rate (280m3/h) as for thr 4" unit for a lower noise level. Is that vaguely sensible or am I missing something?

 

[ericmark]

In my mothers house we have a bathroom extractor and home we don't, in mothers house most of the time it is turned off at the isolator, we get no mould at mothers house, our house always a problem with mould, however still a problem after being empty for 18 months so can hardly blame lack of fan. So why fit a fan?

In mothers case the building inspector said it was needed, he pointed out could not open window as on ground floor and any visitor could look in. In our house we have found why mould, cracked tile on the roof.

So yes there is some point in removing moisture, however often being removed slowly is better, as too fast means cold draft, so likely the 4" will be enough, fit a 5" and the cold draft will mean it is switched off. Just ensure there is a run off for any condensed water.