Toilet fan

[cdbe]

Hi, can anyone recommend a fan for my new small (1.3m x 0.8m) ground floor internal toilet?

It's got to duct up through the first floor bedroom in a stud wall then across the loft.

The ducting is: 1x round to flat channel adaptor, 3m of 240mm X 34mm flat channel ducting vertical, 1x flat channel to round adaptor, 4m of 100mm round flexible ducting to soffit.

I believe the required extraction rate is quite low for just a WC but obviously want something that will effectively remove odours in this situation.

I don't need anything fancy but it will need a timer.

Thanks in advance.

 

[muggles]

Try TLC Direct - they have a calculator for duct lengths and extract rates

 

[John D v2.0]

Change the 4m of Flexi for rigid for as much of the length as possible. You'll need less than 10l/s extraction, but with 4m of Flexi the fan will struggle.
Flexi is like River rapids for air, constantly swirling back on itself, smooth bore lets it run as one mass of air so there's a huge difference.

 

[cdbe]

Thanks, the calculator says 6l/sec - I've bought a VSF100T which is 20l/sec. I suspect I'm way over the recomended ducting length for this but I think it's worth a try for £13. I will duct through 110mm soil pipe across the loft.

 

[JohnD]

this sort of thing is much more suitable for a ducted fan
https://www.tlc-direct.co.uk/Products/SLTDK160T.html
there are cheaper ones.

And some that are rated as high as 240 cu.m/hr

A typical basic fan is usually rated at about 80 cu.m/hr, which is sufficient for a bathroom if you run it every use, with a timer, but will be overwhelmed by a steamy shower, and probably insufficient if you derate it to allow for a long duct..

I don't work in litres per second, but I understand 20lps is about 72 cu.m/hr

https://www.convert-me.com/en/convert/flow_rate_volume/liter_s.html?u=liter/s&v=20

edit
sorry, I see yours is just a WC. I have an 80cu.m "silent" fan in mine. No duct. I would not want less. People often grumble about the noise of fans, but the latest "silent" ones are very quiet. They cost more than £13, though. Manrose is a budget brand and the fan you chose is 41.0dB(A) noise level which is quite noisy.

 

[cdbe]

Thanks, I'm on a tight budget and fan will be up in loft so noise not an issue. I found this while browsing on eBay and thought it was quite simple and informative for others who are interested in the affect of ducting length:

Looks like each metre of (flexible) ducting reduces the extraction rate by 2 l/second so with my proposed set up it ain't going to suck much out! I'm now thinking to try just terminating in the (well ventilated) loft which is 3m up (it's just dry ''toilet" air rather than heavy moist shower air).

Obviously if it doesn't work I'll have to shell out for a better fan - but I do have a thing about not wanting to go OTT and be extracting excessive amount of warm air out of the house in the winter.

 

[John D v2.0]

I'm now thinking to try just terminating in the (well ventilated) loft which is 3m up (it's just dry ''toilet" air r

That would render all your vapour barriers useless, dry toilet air at 20c added to dry loft air at 1c would make very wet loft air at 3c. Warm air holds a lot more moisture than cold air, hence you get condensation on cold surfaces eg Windows