How to fit a good in line bathroom fan in loft and reduce noise?

Buffman · 20 May 2022 at 14:57

Hi all,

Im renovating my bathroom and want to put a centrifugal fan in the loft.

Ive already got the electrics sorted I just want to know best way to dampen noise?

Should I make a timber frame hanging from the purlins?

Could I mount the fan vertically and point it straight out the loft almost? Any advice on how to avoid condensation?

Is there any particular brands that are good?

I was going to use this fan cover (probably size 100mm unless someone can convince otherwise?)

https://www.amazon.co.uk/dp/B004X4SZ92/ref=cm_sw_r_apan_i_RVAMDJVYHPQGBJDY35ME?psc=1

Considering this fan

VENTAXIA ACM100T Mixed Flow Inline Duct Extract Fan

Shop Mixed Flow Inline Duct Fan with timer for 100mm ducting. Offers 2.5 times pressure of conventional axial fans, and are dimensionally more compact.

www.i-sells.co.uk

Or would something like this be far better?

6''/150mm In-Line Duct Extractor Fan - Silent 500m3/hr c/w Timer | Soler_&_Palau (5211366400)

I was going to use 150mm flexible insulated ductwork which I already have from another project. In that case should i go with larger diameter fan or is it OK to jubilee clip ducting at ends?

Is there any issue with using Flexi ductwork? Rigid wouldn't work too well in my situation but I'll try avoid bends.

Im currently boarding my loft out and can see in situ progress pics below

The old fan is located behind the attached (can see white ducting) with the fan tied straight onto the ceiling header joist.

Other side of loft

The bathroom is not yet finished but is being tiled next month the fan will be going above where the shower is (on the right of this photo)

ANDARIAL · 21 May 2022 at 08:40

Buffman said:
Could I mount the fan vertically and point it straight out the loft almost? Any advice on how to avoid condensation?

Not a good idea with this type of fan as condensation`could`drip back into the fan .Mount horizontally with a drip loop in the ducting.Also insulate the duct or get some already insulated.Mounting the fan onto a flexible substrate like kingspan or rubber may help

But keep the fan open to the air to avoid overheating

Buffman · 21 May 2022 at 18:37

ANDARIAL said:
Not a good idea with this type of fan as condensation`could`drip back into the fan .Mount horizontally with a drip loop in the ducting.Also insulate the duct or get some already insulated.Mounting the fan onto a flexible substrate like kingspan or rubber may help
But keep the fan open to the air to avoid overheating

when you say drip loop do you mean a condensate drop out line? I'll try without at first as even if it drops out it would be back into the shower tray. also I have some 150diameter ready insulated ducting so I think I'll use that

Mysterae_ · 21 May 2022 at 19:56

I don't like the flexible ductwork as it's a place for condensation, moisture and fluff to accumulate then it'll slowly start to rot. It'll be okay if you plan to maintain it every year or so, checking for water build up.

I used soil pipe for my installation and I think the same fan as the one you suggested, I posted it a while again I remember. It's a good fan with plenty of air movement but can be a bit noisy, but to be fair most suitable fans are.

y4mrLSwZhdyBkXubg9cTr9IuvjdRzlZ1eEtdwrA4ZjIc79vXuTFRofnYHw4u89u7Ae_M8NF278LUtzdWksiDKESjMx9sGObhBqk4ugQFpFlfcdUEZawOubyOTaoYqtrka7WXGl0DcrFXwQzLI_NbQm7gM6aEiEAuaMmBuOAT6qsgGo

One poster mentioned about condensation building up on the un-insulated pipes but the one place it did build up was on the fan itself. I'm planning on insulating it with a foil blanket, I don't think there's any need to work about heat build up of the fan.

theone8181 · 21 May 2022 at 20:39

Mysterae_ said:
I don't like the flexible ductwork as it's a place for condensation, moisture and fluff to accumulate then it'll slowly start to rot. It'll be okay if you plan to maintain it every year or so, checking for water build up.

I used soil pipe for my installation and I think the same fan as the one you suggested, I posted it a while again I remember. It's a good fan with plenty of air movement but can be a bit noisy, but to be fair most suitable fans are.

One poster mentioned about condensation building up on the un-insulated pipes but the one place it did build up was on the fan itself. I'm planning on insulating it with a foil blanket, I don't think there's any need to work about heat build up of the fan.

Flexi pipe will also reduce how much air gets sucked out, not sure if that makes a difference in this application though.

rodders · 21 May 2022 at 21:05

I used Flexi over a distance like that before and it really impedes the flow.
Changed to smooth bore and it was so much better.

Buffman · 21 May 2022 at 21:38

Mysterae_ said:
I don't like the flexible ductwork as it's a place for condensation, moisture and fluff to accumulate then it'll slowly start to rot. It'll be okay if you plan to maintain it every year or so, checking for water build up.

Wow that's a neat install. Were you not tempted to tie it from rafters?

Ive gone for the 250quid fan above, but will just use insulated Flexi and see how I get on. I figure it's a 150mm diameter so should be fairly good.

Mysterae_ · 21 May 2022 at 21:48

Buffman said:
Wow that's a neat install. Were you not tempted to tie it from rafters?

Ive gone for the 250quid fan above, but will just use insulated Flexi and see how I get on

Thanks, never thought about tying it to the rafters in all honesty! I wanted a short as run as possible as I had to make a new hole in the outside wall for the vent - the previous owners didn't.

£250 for a fan seems like a lot, I think my Vent Axia one was half that price.

Buffman · 22 May 2022 at 01:00

Mysterae_ said:
Thanks, never thought about tying it to the rafters in all honesty! I wanted a short as run as possible as I had to make a new hole in the outside wall for the vent - the previous owners didn't.

£250 for a fan seems like a lot, I think my Vent Axia one was half that price.

Yeah I've seen them tied to rafters before for the same reason of noise transfer. I think making it from fully rigid ductwork is good, but just a bit of a pain in the arse for a lot of setups

Participant · 22 May 2022 at 06:43

In terms of what to mount it on, I've used gardeners' kneeling pads before to good effect.

theone8181 · 22 May 2022 at 07:14

Participant said:
In terms of what to mount it on, I've used gardeners' kneeling pads before to good effect.

Anything a bit squishy will do. You can get proper rubber feet with a tapped hole in them bit it's probably overkill

.

ANDARIAL · 22 May 2022 at 08:28

We have got a soil pipe duct in the ensuite as well but we find it a bit noisy and echoy.
Re drip loop i mean in the length of duct make a section lower than the fan either side somewhere.Personally i do not think covering the fan is a good idea heat wise.Just my opinion

Mysterae_ · 22 May 2022 at 08:51

ANDARIAL said:
We have got a soil pipe duct in the ensuite as well but we find it a bit noisy and echoy.
Re drip loop i mean in the length of duct make a section lower than the fan either side somewhere.Personally i do not think covering the fan is a good idea heat wise.Just my opinion

I totally understand and I'm second thinking it, perhaps a small drip pan underneath to catch the moisture would be better. I'll go in the loft later and take a picture of the staining on the floor the moisture has caused.

Buffman · 22 May 2022 at 14:25

Participant said:
In terms of what to mount it on, I've used gardeners' kneeling pads before to good effect.

Cheers that's a good idea! Might do the same and get a new one. Did you fit yours to loft floor or ceiling?

Buffman · 22 May 2022 at 14:26

ANDARIAL said:
We have got a soil pipe duct in the ensuite as well but we find it a bit noisy and echoy.
Re drip loop i mean in the length of duct make a section lower than the fan either side somewhere.Personally i do not think covering the fan is a good idea heat wise.Just my opinion

No I wouldn't insulate or cover the fan. I will insulate the ductwork /use insulated ductwork

jpaul · 22 May 2022 at 21:03

Is there any fall on the horizontal section ... wouldn't the vent at the start and a fall give drainage potential ?

Do you have an automatic shutter in the bathroom - ours doesn't and in winter time have an improvised cover in the bathroom, otherwise the heat disappears.

Tesla · 24 May 2022 at 23:32

Mounting the fan to the rafters instead of the ceiling joists will greatly reduce the fan hum noise in rooms below.

Gammawolf · 25 May 2022 at 16:36

Buffman said:
Wow that's a neat install. Were you not tempted to tie it from rafters?

Ive gone for the 250quid fan above, but will just use insulated Flexi and see how I get on. I figure it's a 150mm diameter so should be fairly good.

Jesus, £250 for a fan. Screwfix has the Manrose MF100T 100MM for £100 which even still seems expensive as i'm sure i got my 3 for £60 each a couple years ago.

Buffman · 25 May 2022 at 19:27

Gammawolf said:
Jesus, £250 for a fan. Screwfix has the Manrose MF100T 100MM for £100 which even still seems expensive as i'm sure i got my 3 for £60 each a couple years ago.

Aye a bit expensive but I guess the equivalent would be the same sized 150mm fan from manrose. It's a bit of a monster size but we'll see how it performs. I already had a 150mm holesaw so that's saved me 30 quid

Ive never had the novelty of a bathroom without condensation problems! For an extra 100 quid or so it's inconsequential compared to the rest of my new small bathroom, all costs are mental at the moment. Think it's gonna cost me around 8k to 10k supply and labour for my bathroom and I did a lot of the fitting myself (got a tiler/Plumber in for some of the harder bits)

Due to the position of the roof tile outlet I think I'll need to mount it to the floor boards.

Reuben klang · 25 May 2022 at 22:20

Gammawolf said:
Jesus, £250 for a fan. Screwfix has the Manrose MF100T 100MM for £100 which even still seems expensive as i'm sure i got my 3 for £60 each a couple years ago.

I agree, that seems ridiculously high, although it is a 150mm fan so should be far superior be interesting to see real life results with the humidity from a shower.

*edit*

Post above loaded, while i was researching/replying. Would be good to see an update once you get everything going. I guess it’ll breeze it due to the bigger size. I hope it does as I too may have to upgrade!