Insane bathroom condensation

[Ivor Windybottom]

I told my other half she can use the squeegee in the crappy old shower, but I don't want it scratching the screen and tray in the new one. The amount of water left there is probably insignificant compared to the towel that's cooking away on the towel rail and wicking into the air.

I prefer having a shower and walking away without messing about. Decent bathroom cleaner gets the limescale marks straight off without any rubbing.

 

[MartyJ]

Just a bit of an update, post testing... Left the bathroom door completely open and ran the shower for 30 mins.

Top 2-3 lines of tiles around whole room started to get moisture build up after around 10 mins and stayed fairly stable at "damp" until gone 20 minutes but approaching 30 mins the walls were clearly wet and dripping.

Ultimately message to the family is shorter showers but curious to know if there is any extractor setup that can handle door/window closed and get the room to the 30 mins mark dry?

 

[Murdochcat]

Unless the room is warmer you will never eradicate the damp. That’s the issue

Why is the ceiling so dark ?

 

[MartyJ]

Unless the room is warmer you will never eradicate the damp. That’s the issue

Why is the ceiling so dark ?

Painted black (anti mould paint).

Will do a few tests this week, will run the shower 30 mins with door closed and see at which point it builds up ie max shower length.

3rd experiment...will up the room temp from 21.5 to 23c (or higher) and see how that affects things

 

[JohnD]

Edit

i see your extractor fan. What is its nominal air throughput?

I can't see it.

240 m3/hr is usually enough.

 

[Murdochcat]

Painted black (anti mould paint).

Will do a few tests this week, will run the shower 30 mins with door closed and see at which point it builds up ie max shower length.

3rd experiment...will up the room temp from 21.5 to 23c (or higher) and see how that affects things

I think the fan is the issue and if you do tests on different days the ambient temperature starts to have effects

 

[MartyJ]

Edit

i see your extractor fan. What is its nominal air throughput?

I can't see it.

30L/s when shower on

 

[JohnD]

30L/s when shower on

That's the trouble then. You have a small, weak fan suitable for a WC cubicle, and put a long duct on it. It is inadequate for a steamy shower.

 

[MartyJ]

That's the trouble then. You have a small, weak fan suitable for a WC cubicle, and put a long duct on it. It is inadequate for a steamy shower.

Yes and no. That extractor is one of the most powerful extractors that isn't an inline type. It's certainly the type (and others like it) recommended for normal size bathrooms and 1.4m of ducting cannot be described as long. Unfortunately almost every top website that lists best extractor fan for bathroom etc has these as the top picks whereas they really should be promoting the inline extractor

Inline extractors are a lot more powerful (and great for long duct runs 4m+) but unfortunately there was nothing to suggest this was needed at the time of install but certainly will be looking into that now

 

[mikeey84]

It's certainly the type (and others like it) recommended for normal size bathrooms and 1.4m of ducting cannot be described as long

Are they recommended when they have 1.4m of ducting to go through?

I find it very hard to believe anyone would recommend one of those extractor fans if it was doing anything but going straight through a wall.

What does the TLC fan size calculator recommend?

 

[Murdochcat]

Can you get into the space above the ceiling?

 

[^woody^]

I can't see why you just would not open the window! There is no better way to get ventilation and better air movement and reduced pressure for the fan, and better than any crappy 10mm door undercut. It's just so simple.

Probably too late now, but the fan or input should have been placed over or near to the shower or bath (better extract at source), and perhaps should have been an inline centrifugal fan (most efficient) with a 125 or 150mm flexible duct and no sharp bends (smooth massive air movement).

So unless those are to be altered, the window is the only practical option.

 

[Murdochcat]

I can't see why you just would not open the window!

Simple answer is because in the cooler months you are drawing cool, moist air, into a steamy room creating more condensation

 

[^woody^]

Simple answer is because in the cooler months you are drawing cool, moist air, into a steamy room creating more condensation

Lol. That's an answer to a different problem.

The air being drawn in is going straight back out the fan, not hanging around "creating more" condensation. The condensation is already there, the air input moves it.

 

[Murdochcat]

Lol. That's an answer to a different problem.

The air being drawn in is going straight back out the fan, not hanging around "creating more" condensation. The condensation is already there, the air input moves it.

Not sure I agree with that.