Bathroom condensation

[drd63]

Hi, I’m after help or suggestions please. I have a real problem with getting rid of steam in the bathroom which is just condensing on the walls. I think part of the problem is the ceiling height above the shower enclosure. I have a ceiling mounted extractor fan but this 1m above the height of the shower enclosure and doesn’t seem to be powerful enough to draw the steam up. Any thoughts welcome.

[dmsims]

Steam rises

What is above the ceiling e.g. fan and ducting , where is it routed?

[Jeremy-75qq8]

There are only two possible solutions

1. More ventilation ( open the window when showering or even the door to allow to make sure the door is not limiting extraction rates )

2 make the room warmer as hot air holds more moisture. This is slightly practical if your bathroom is freezing but not if it is already at normal room temp.

That is it. There are no magic solutions

[dobly]

^ as above, balancing insulation, heating and ventilation is key. For an extractor fan to work properly, the (moist) air you suck out has to be replaced by either outside or inside air, usually via the window (summer), or a gap under the door. Without this, the steam will remain, and condense on cold surfaces. It could be that because of poor insulation your bathroom is too cold, made worse by an insufficiently powerful fan and inadequate ventilation, requiring all 3 elements to be addressed.

[Belle427]

Check the fan and ducting as suggested, a long ducting run and a crap fan can be a common issue.
The inline fans mounted in the attic if possible are very good.

[Paul Drawmer]

As previous answers have said: Before changing anything, make sure that air is getting in. If the door and windows are really good fits, then the fan can't work.

[Hereward]

When my older son finishes his epic showers the bathroom resembles a geothermal cave with water dripping off every surface.

I open the window fully, put a 50cm fan on the floor, run the cable under the door to the landing power socket and run the fan full blast for 10 minutes. That sorts the worst of it.

[OutInTheShed]

Our shower enclosure goes up to about 25cm below the ceiling.
There's an inline fan drawing from above the shower and running on for 20 minutes.

I replaced the fan after about 4 years, it got less efficient due to dust and crud.
If you leave the window open in winter, the walls will be very cold and still get some condensation, more so if the weather is damp.
There is always moisture to get rid of from used towels etc, you need warmth and ventilation.
We squeegee the tiles and shower door glass after a shower, that vastly reduces the amount of water needing to be removed by airflow.

[MrC986]

We stripped out the old bathroom in our cottage and had a full rewire done with the refit...the extractor fan is on the outside wall and I was surprised at how long it runs for once you've switched the light off but it does mean residual condensation is very limited once it turns itself off.

[Car bon]

Does the bathroom have a window ?

If it does, then open it wide before getting in the shower.

[Wozy68]

The biggest mistake to rid a bathroom of condensation is opening a window. …. If the air temp outside is colder than the temp inside, the fan will draw cold air in, hit the warm air of the bathroom and cause even more condensation. The only time to have the window open is when it’s warm/hot outside.

The fan in a (especially) small room will require airflow to work correctly so keep the door slightly ajar after showering etc as the air in the home will be warmer so will cause less chance of causing more condensation.

Lastly the fan should run for at least 30 minutes afterwards.

[Mont Blanc]

Wozy68 said:

The biggest mistake to rid a bathroom of condensation is opening a window. …. If the air temp outside is colder than the temp inside, the fan will draw cold air in, hit the warm air of the bathroom and cause even more condensation. The only time to have the window open is when it’s warm/hot outside.

The fan in a (especially) small room will require airflow to work correctly so keep the door slightly ajar after showering etc as the air in the home will be warmer so will cause less chance of causing more condensation.

Lastly the fan should run for at least 30 minutes afterwards.

You can actually see this effect in action if you open the window mid-shower - A relatively steam-free bathroom with suddenly fog up massively in seconds when the cold air enters.


As for my own issues:

I moaned about my en-suite bathroom steaming up during showers recently, and everyone said to fit a bigger fan, ensure ventilation into the room when the fan was running to allow plenty of incoming air, and make sure there was heating in the bathroom to help keep the air warmer and dry things out.

1) The incoming air isn't an issue as trickle vents are always open on the windows, and I also have the window vented on the latch permanently. Plus, there is a decent gap under the bathroom door to allow air to be drawn in.

2) I checked the fan, and it turns out that the one fitted has a nice short run of ducting, and also has the highest airflow rating you can buy, and is turned up to maximum flow.

3) I added an electric heating element on a programmable timer to the towel rail radiator to keep the bathroom warmer.

It still steams up massively during showers. I don't think there is much you can do about it to be honest. It's just really annoying. I open the window wide after showering for about 30 mins to let it dry out.

[fouronthefloor]

Run the shower cold for about a minute after showering and the condensation will disappear.

[OutInTheShed]

Mont Blanc said:

...
It still steams up massively during showers. I don't think there is much you can do about it to be honest. It's just really annoying. I open the window wide after showering for about 30 mins to let it dry out.

If you can contain the steam to the shower cubicle, the rest of the bathroom can remain dry and condensation-free.

This also means you're not using the shower to heat the whole room to 38degC, just the cubicle.

Trendy walk-in showers and wet rooms etc have a big H&V running cost!

We have a shower door which closes with a reasonable gapover the top, so the fan contains the steam in the cubicle.
Dry towels, no issues with steamed-up mirrors, sorted!

I've stayed in a lot of hotels and airbnbs with very shiny, but utterly dysfunctional bathrooms!
Things which are nice in a California climate can be a bit knobby in Wales or Devon.

I've been looking at houses to buy, there is a lot of designer tat out there growing mildew.

[sherman]

Just had our bathroom redone.
We had an Icon15 fan installed.
It seems to have alot more powerful suction than what we had before.
It has an over run that runs fof about 10mins after you turn the bathroom lights off. It leaves the room nice and dry.
Also the fan cover does a cool swoopy thing with its cover as it starts up.

https://www.toolstation.com/airflow-extractor-fan/...

[dmsims]

Most wall mounted axial fans are just rubbish

I went through 2 (the last one a Helios) before fitting a centrifugal fan

They also have run on times that are short and the humidity controls are a joke

I added a Zibgbee relay, humidity sensor and a fan blueprint to Home Assistant - happy days!

https://community.home-assistant.io/t/bathroom-hum...

Edited by dmsims on Saturday 4th May 18:15

[AlexC1981]

My bathroom doesn't have an extractor, but it does have a wall mounted fan heater. In the winter after a shower, I open the window and run the fan heater whilst I'm drying off + another 5 minutes or so, and it soon clears up.

They might make your bathroom look 30 years out of date, but bathroom wall fan heaters are absolutely wonderful when you step out of a hot shower or bath and the room is chilly!

[Mont Blanc]

OutInTheShed said:

Mont Blanc said:

...
It still steams up massively during showers. I don't think there is much you can do about it to be honest. It's just really annoying. I open the window wide after showering for about 30 mins to let it dry out.

If you can contain the steam to the shower cubicle, the rest of the bathroom can remain dry and condensation-free.

This also means you're not using the shower to heat the whole room to 38degC, just the cubicle.

Trendy walk-in showers and wet rooms etc have a big H&V running cost!

We have a shower door which closes with a reasonable gapover the top, so the fan contains the steam in the cubicle.
Dry towels, no issues with steamed-up mirrors, sorted!

I've stayed in a lot of hotels and airbnbs with very shiny, but utterly dysfunctional bathrooms!
Things which are nice in a California climate can be a bit knobby in Wales or Devon.

I've been looking at houses to buy, there is a lot of designer tat out there growing mildew.

I suppose it depends what you want from a bathroom. I have had ‘cubicle with door’ showers in the past and I really don’t like them. Walk in showers, or wet rooms type showers, without doors are popular for a reason and it isn’t all for aesthetics.

If I had to choose between steam in my bathroom or going back to a door/cubicle design, I would still stick with the steam!

[caziques]

Mont Blanc said:

I suppose it depends what you want from a bathroom. I have had ‘cubicle with door’ showers in the past and I really don’t like them. Walk in showers, or wet rooms type showers, without doors are popular for a reason and it isn’t all for aesthetics.

If I had to choose between steam in my bathroom or going back to a door/cubicle design, I would still stick with the steam!

The only real way to stop condensation is to have an enclosed shower cubicle.

I have four bathrooms, every one has a lid on the shower cubicle - none of them have an extractor fan. Zero condensation - except when having a bath.

Any sort of walk in shower is asking for trouble.

[TwigtheWonderkid]

Wozy68 said:

Lastly the fan should run for at least 30 minutes afterwards.

Can't you just do the maths to set the run on time. If your fan has a clearance rate of 180 cubic metres / hour, and your bathroom is 36 cubic metres, you need a run on time of 12 mins.