Bathroom extractor

[crystal ball]

Been asked to price an extract fan for a bathroom 3m x 3m, north facing fully tiled, lots of condensation & a fair amount of black mould, my opinion is that a fan will have little effect if any, thoughts please

 

[EFLImpudence]

I agree with you, but not everyone agrees with me.

Presumably it could be better than nothing, but
it could drag in humid air from the rest of the house which will just cause more condensation in the bathroom.


Thinking fans can prevent condensation and/or magically remove all humidity from bathrooms is misguided.


People do not expect a little machine in the wall to remove dust and dirt from houses; they know they have to sweep up/vacuum and remove it themselves, yet wiping up condensation, removing it, and cleaning mould seems to be an unthinkable thing to do.

 

[JohnD]

it could drag in humid air from the rest of the house

It is most unlikely that the rest of the house could contain air as humid as the room where you have steamy showers and hot baths

my opinion is that a fan will have little effect if any

Why is it your opinion that removing water vapour from the bathroom will have "little effect if any?"

If the customer wants one, and the room is particularly humid, I'd suggest something more powerful than the £12 cheapies that builders like to fit.

Small 100mm fans usually have an extract rate of about 80 cu.m/hr which is hardly enough, even in a well-heated and insulated room without a shower. If you fit a 6-inch fan it can be much more powerfil (if there is not already a duct in the wall then there is no need for a little fan)

To be effective, you will get better results if it comes on with the light switch and has a timed run-on. 5 minutes may be enough to freshen the air, but after a steamy shower it will probably need 20-30 minutes because the walls, tray, and towels will need to dry off. Humidstat ones are I find nowhere near as good, though the idea often appeals.

If you can fit a ducted one above the ceiling, you can get more power and less noise.

Modern, good quality fans with ball-bearing motors can be very quiet. Noise is a thing that householders moan about, and many of them refuse to use fans if they are noisy.

This is a good-quality 6" fan with timer. There are cheaper brands that are not as good. If you make a 6" hole and the customer insists on a cheap, weedy fan, it can be replaced later with little effort.
https://www.tlc-direct.co.uk/Products/SLS300CRZ.html

If looking at others, compare the noise (db) and the airflow (cu.m/hr)

This horrible cheap fan, loved by builders, is the worst one I know. Observe that it is noiser and not as powerful.
https://www.screwfix.com/p/manrose-xf100s-15w-bathroom-extractor-fan-white-240v/11097

Good luck!

 

[EFLImpudence]

It is most unlikely that the rest of the house could contain air as humid as the room where you have steamy showers and hot baths

I didn't say it would be "as humid" but it will not be dry.
Several people, animals, drying washing, plants, fish tanks, cooking etc.

Depending on the situation, it might be better to have a fan in the kitchen.

 

[JohnD]

I didn't say it would be "as humid" but it will not be dry.

If you replace humid air with less humid air, you will reduce condensation. Bathrooms suffer condensation because they are steamy due to baths and showers. Removing this steamy air is bound to reduce it.

 

[EFLImpudence]

If you replace humid air with less humid air, you will reduce condensation. Bathrooms suffer condensation because they are steamy due to baths and showers. Removing this steamy air is bound to reduce it.

Reduce means there will be some left.

So not curing the mould and having little effect as Crystal Ball was asking.

 

[JohnD]

My bathroom has an extractor fan, which draws air in, under the door, from the rest of the house.

how much condensation do you think I get?

How do you think that compares with the same room before I fitted the fan?

 

[EFLImpudence]

My bathroom in Bournemouth did not have a fan, which drew air in, under the door, from the rest of the house.

How much condensation do you think I got?



Houses are different. Fans are not a magic solution.

 

[EFLImpudence]

Plus. You must have missed this bit:

Presumably it could be better than nothing, but

 

[crystal ball]

Why is it your opinion that removing water vapour from the bathroom will have "little effect if any?"

Just from personal experience, my own bathroom has a fan and it may have some beneficial effect but it is not noticeable I get more results by leaving the window open

I called at this house yesterday around noon and the shower had not been used for a few hours and it was dripping down the walls, an in line fan is not feasible

 

[JohnD]

own bathroom has a fan and it may have some beneficial effect but it is not noticeable

Sounds like your fan is not much good (or is not being turned on enough)

Both are common.

 

[crystal ball]

100mm fan, no room for any bigger, runs all day sometimes when Mrs CB forgets

 

[cwhaley]

A fan will have an effect in that it will remove x amount of water vapour and air. Nothing beats opening a window after a shower but a good in-line fan (like mine, which extracts up to 280 L/hr) will make a difference. Have a shower without a fan like that on and you'll notice!

 

[JP_]

Suggest also insulating the loft out to the max - if I had really bad problem I'd stick insulation board down in the loft. If there is the ceiling height to play with, maybe overboard with new insulation backed plasterboard? But still check loft is properly insulated.

I have a fan heater in my bathroom - sits near the ceiling, pull cord. It makes a huge difference as raising the temperature allows the air to carry more moisture, so extractor pushes moisture out faster.

Insulation, heat, ventilation - all 3 needed to properly reduce condensation and mould.

 

[cwhaley]

I have a fan heater in my bathroom - sits near the ceiling, pull cord. It makes a huge difference as raising the temperature allows the air to carry more moisture, so extractor pushes moisture out faster.

I'm interested in one of these as although we solved the condensation problem in our bathroom (sorry to hijack the post), the inadequate towel heater means the bathroom can be unpleasantly cool in the winter. Do they cost much to run?