Recommendations for Bathroom Extractor Fan

Most of the feedback I read about those 3 blade shutters to stop backdraught are that they are extremely noisy in any sort of wind. I live right beside the sea and quite regularly have high winds hitting the house.

I have seen cowls for the outside that have one single flap inside them. I guess these would work better than 3 blade shutters on their own as the cowl would stop wind directly hitting the single flap. But I wonder would extractor fan produces enough force to open a single flap?

I guess you could always put a cowl over 3 blade shutter also?

chuck eastwood wrote: »

https://www.amazon.co.uk/dp/B005FPD49E/ref=cm_sw_r_apa_i_3zVNEb3AH2QCQ

First one I fitted when I moved into our house 10 years ago. Still going. Second fitted in a new bathroom down stairs 3 years ago.. The blades are a good seal and relatively quiet. What most people dont get is that a fan subtle for a decent size bathroom will need to have sufficient airflow through it thus creating noise due to ait displacement 45db and above. The above unit can be fitted with a timer or humidity stat. Both work well but are cheap

Thanks. I see that fan extracts at 19 l/s and sound level is 35 dB.
The envirovent Silent 100 extracts at 26 l/s and sound level is 26 dB

The envirovent produces 25% less dB. I'm not sure exactly of the relationship between reduction in dB versus perceived reduction in noise levels, but it's definitely not 1 to 1 i.e. a 25% reduction in dB would result in the fan sounding a lot more than 25% quieter.

Sounds like the Envirovent would is not a bad choice?

How do you work out what airflow is sufficient for a bathroom?

chuck eastwood wrote: »

To be honest most standard 4 inch fans give more or less the same output. If you want more then an inline fan is needed but here is one way to calculate it


divide your bathroom's volume by 7.5. For example, a bathroom with a volume of 1000 cubic feet (28.3 cubic meters) needs a fan capable of moving (1000 / 7.5) or 133 CFM (3.8 cubic meters per minute)

Yeah they all seem to be around the 20 l/s. Envirovent extracts 37% more than iCON one you mentioned though. That's quite a significant difference.

Thanks. I'll work that out what airflow I need based on that.

One of my fans is in bathroom that is not on an external wall and the pipe runs for somewhere between 2m to 2.5m. How do I figure out if a fan is sufficient for running that length of pipe?

This guy has some interesting videos where he tests various extractor fans. He tests the two we mention here

Icon 15 https://www.youtube.com/watch?v=tGiwXbV7k_s
Envirovent Silent https://www.youtube.com/watch?v=95eqvUAYuCQ

They both perform around the same 18 l/s.

From the look of the design it seems the Icon would perform better for stopping back draught. How do you find yours? Does it block back draught 100%?

The Environvent uses a flimsy piece of plastic at the back of the unit, relying of gravity to make it drop back down when fan is off and expecting it to seal well enough. Whereas the Icon mechanically closes the vent from the front of the unit. Over time, you'd have no way of easily checking if Envirovent is back draughty mechanism is working correctly, whereas you can easily see if the Icon is working correctly. You'd imagine the flimsy plastic on the Envirovent would eventually get pretty dirty and it would not seal correctly.

Interesting too that this guy says the cheaper vents don't even meet the 12 l/s required by UK regulations, and if you put a back draught on grill on the outside of the house then they fall way below the 12 l/s required.

chuck eastwood wrote: »

https://www.amazon.co.uk/dp/B005FPD49E/ref=cm_sw_r_apa_i_3zVNEb3AH2QCQ
The above unit can be fitted with a timer or humidity stat. Both work well but are cheap

Did you fit a humidity stat? Wondering how well these work and how they work?

With humidity stat is it controlling on\off or just off i.e.:

ON\OFF) Sensing humidity levels 100% of the time, and it triggers fan comes to come on when level is above threshold and triggers fan to go off when level falls below threshold?

or

OFF) Sensing humidity levels only when you switch the fan on, and it triggers fan to go off when level falls below threshold?

BrownFinger wrote: »

Here is something I fitted in my own place recently .
I only wanted the fan to come on when the shower was on ,not when the lights were on.
So I fitted the current sensing device on the shower feed.

https://www.amazon.co.uk/gp/product/B07SLBCR5H/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

Oh, thanks! That's a pretty nice idea for a bathroom with shower only, like ensuite.

Hintel wrote: »

I fitted one of them at home wired it into the shower circuit with a current sensing relay , used solid ducting

Does yours have a humidity sensor? I'm curious as to how these work - if they control "on\off", or only control "off" once something else has triggered it "on".

Anyone got experience with humidity sensors on extractor fans? How do they work - control on\off or just off? How do they fare over time, are they still working accurately a few years after installing?

I've looked at some models with a humidistat. It seems they control on and off.

I was in two minds about how beneficial they would be. But then I was thinking about my utility room which has a condensing drier. It blows hot hair into the room and I can't imagine it's 100% efficient at gathering the water in the container you empty. The air coming out of the drier most likely contains higher than normal levels of moisture. A humidistat extractor fan would be ideal for a utility room I think.

A normal timer fan usually has max overrun of 30min. If you put your drier on, leave the utility room turning off light, then fan won't be running for most of drying.