Bathroom extractor fans

[ShaunB]

Bathroom Extractor Fans
Guys

The extraction rate on my existing extractor fan is very poor - 137m3/hr.
https://www.hib.co.uk/products/venti...te-led-chrome/
Walls are covered in condensation from the steam after showering.
The fan is working ok, because if you hold a bit of toilet paper up to it, it will hold it there, and the outlet is not covered up.

I've come across this which is 245m³/h, so substantially more, and seems to get very good reviews.
https://www.screwfix.com/p/manrose-m...ails_container

Can you recommend any?

 

[roheel]

Check out the envirovent extractor fan that's humidistat controlled. I have the mains voltage one installed with the wireless boost button. Works great and the best I've had!

 

[whitenemesis]

Make sure you have sufficient replenishment air coming into the bathroom. A high level vent to an adjacent room/area will allow warm air to enter the bathroom when the extractor fan operates

 

[ShaunB]

The existing inline extractor is in the loft, close to to the bathroom vent, and has maybe 5 foot of vent to the outside wall

 

[whitenemesis]

If the extractor is close to the vent then the air won't be extracted from the rest of the room.
Ideally vent and extractor should be at opposite sides, so airflow across the room

 

[mercmancdi]

I have a window in my shower room and 4 wks ago stupidly got a extractor fan fitted.
Worse thing I could have done , the fan doesn’t clear the condensation unless it’s on for ages
and lost my soundproofing as well .
I open window for 5 minutes and it’s all clear.
Going to throw the trip on it and close it up.

 

[ShaunB]

perhaps i've got it wrong, i know that there is about 6 or 7 foot between the vent in the bathroom ceiling, and the vent on the outside wall. I've assumed the extractor fan is close to the ceiling vent, but will climb into the loft tomorrow and look.

I've been reading, and found this, so I just assumed this is how they installers setup mine.
Ventiliation Guide | Extractor fan fitting information Epicair.co.uk


Rule Two - Siting your Fan In order to maximise the effectiveness of your fan, there are a few things you should consider. It needs to be as close as possible to the source of the steam but as far away as possible from the source of replacement air. The diagrams below show 'Poor Circulation' and 'Best Circulation'. The 'Poor Circulation' diagram shows the fan next to an open window. Fresh air coming in through the window is being sucked out immediately.

 

[190]

The performance of normal axial fans deteriorates markedly when they have to push air through a long hose. They can't cope with a big differential pressure and are in fact hopeless in this situation. What you need is a centrifugal fan which is designed to overcome the pressure drop in a long hose. Take a look inside a quality cooker hood and you will see a centrifugal fan. Your car heater fan ditto. Axial fans just don't work well except when they are mounted directly in a wall or window where there is negligible pressure drop.

 

[Benzowner]

Warm vapour will always condensate on a cold surface and unless you can change the whole volume of air in your bathroom in a few seconds, you will have running water on the cold walls, Is your current extractor operated by moisture content as well as on/off light switch and does it continue running after you turn off the light?

I use a tablet type dehumidifier in my bathroom as well as extractor especially during the winter months.

 

[ShaunB]

If the extractor is close to the vent then the air won't be extracted from the rest of the room.
Ideally vent and extractor should be at opposite sides, so airflow across the room

OK, was in the loft today, and my assumption was totally wrong.
The fan is not near the bathroom vent, its probably about 6 foot away and is near the vent on the outside wall.
I purchased the manrose 245m3/hr fan on Saturday from screwfix and installed it in place of the old fan earlier today.
Doing the bog roll test, its substantially more powerful than my old fan.
With the old fan if you held a bit of bog roll right up to the vent it would hold it, but you had to put it almost touching before it would hold.
Same test with the new one see it take hold of the paper from about 2 inches.
The new fan seems quite a lot quieter than the old unit also, time will tell I suppose whether it makes a difference or not

 

[ShaunB]

Warm vapour will always condensate on a cold surface and unless you can change the whole volume of air in your bathroom in a few seconds, you will have running water on the cold walls, Is your current extractor operated by moisture content as well as on/off light switch and does it continue running after you turn off the light?

I use a tablet type dehumidifier in my bathroom as well as extractor especially during the winter months.

The fan is on a separate switch and independent to the lights so you can keep it on as long as need be

 

[ShaunB]

So far so good, first shower test passed