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The main bathroom in our house is regularly (but not excessively) used by three teenagers and it gets a bit hammered at times – when all three have showers one after the other, or one person has a really long shower, the build-up of condensation is pretty bad and, despite only being repainted a few months ago with good quality paint (Jonstone's Trade water-resistant stuff), it is starting to feel the effects already. The bathroom is 3m x 2m and we have a Manrose MF100 inline fan (with the vent directly above the shower head) but it can't cope with the amount of steam generated. The door to the bathroom has a small gap under (but not massive) so there *should* be enough air movement.
Should that fan be able to shift that amount of damp air efficiently in a room that size? Is the vent in the wrong place? Is there anything else I can do? The one thing I do wonder about, though, is that I had to step the ducting down from the 100mm circular to a 110mm x 54mm rectangular duct in order to get it to fit through the eaves so this does restrict airflow a bit, but surely not enough to make it that inefficient?
Any ideas anyone?
No window to open?
Do you have a dehumidifier?
My bathroom is currently without an extractor fan, so I just pop the dehumidifier near the doorway when I feel it needs it.
We run our dehumidifier after showers.
We have same size room and 3 'young adults' and same in-line manrose.
It is fully tiled and has plastic ceiling. Much more resilient to damp.
We open window when warm enough and leave it open for long enough to really make a difference.
In cold of winter we leave the fan on for a long while after showers.
If they use the shower for too long I flick on a tap downstairs....
I had a similar issue and recently upgraded the ceiling mounted 100mm fan to an inline 150mm fan with insulated ducting that vents outside. It felt like overkill when I placed the order but so far so good, it clears the room pretty much instantly even on a cold day.
I have the exact same fan and ducting setup, and the same problem.
100mm round duct is 7854mm^2
110x54 is 5940mm^2 so you lost a wee bit there. I’ve been contemplating adding a 100mm round tee piece before going into two off 110x54 ducts to help the fan out.
also, have you checked the fan is running at max speed. There’s a jumper under the cover to choose between 3 speeds.
opening a window is not ideal as it brings in cold (albeit dry) air. Ensure the area of the gap under the door is at least 8000mm^2.
The main bathroom in our house
Can't your offspring split their washing and preening regimes between some of your other bathrooms?
We just have to have the window open in addition to the wall extractor fan, though my wife and son conveniently seem to forget as it's too cold with it open. Invariably I end up going in after to open the window and curse at the drips on the ceiling.
Rented house so not much more we can do other than get a dehumidifier as above.
My teenage son is the main issue, takes for ever to get him in the shower and then he's in for hours 🙄
How long does the fan run for after the light is turned off? Increase that setting so it runs for longer once they have finished?
Ours runs for 8 or 10 minutes
Are there different settings for your fan? Turns out ours was on the lower setting, so switched it to the higher which helps.
I've got a Pro breeze £60 and also one of the multipack ones. No damp whatsoever. Open the window after a shower too.
How warm is it in there? We used to get really bad condensation in the bathroom, and the only heating in there was a towel rail - great for warming towels, crap for heating a room. Cold air will hold little moisture, so it gets dumped on the walls. We've just had a radiator put in and it's made a massive difference, as it keeps the moisture in the air long enough to let the fan suck it out.
I also need to get up the loft and increase the time the fan runs for, but the hatch is tiny and in a really awkward place
I've got a similar issue - we have an Aventa AV100T inline fan, which I guess is largely the same thing.
I keep debating upgrading to a 125 or 150mm version. The duct out to the soffit on ours gets quite squished as it has to squeeze between some woodwork in the loft. I do wonder how much of the problem is down to that. I keep meaning to spend some time testing stuff out, but it's way down the 'to do' list.
What I have found is that in cold weather, opening the window is worse than leaving it shut (if you have sufficient flow under the door.
The cold air hits the fully saturated hot air in the bathroom & all of the water condenses on the walls & ceiling. If you keep the window shut & let the extractor do its thing, then it removes the saturated air, before the water condenses out.
We have a cold outside wall, which is always the worst for drips & mould. When we finally get round to re-doing the bathroom, I'll probably get extra insulation put against that wall to try & reduce it.
Things to check
- is the fan actually drawing air in - on ours you can feel it, if you place your hand close and if you put a sheet of loo paper near the vent, it gets sucked into the opening. You can also feel the fresh air being pulled into the bathroom if you stand barefoot right next the closed door.
- can you turn the fan up, if it's not on it's high speed setting. I keep meaning to check this on mine.
Partner's house has this issue, but I'm sure it is mainly due to it being 130 years old and generally cold...I'm in the shower before the heating turns on, so it isn't warm and things condense much quicker.
Might look at a dehumidifier but suspect I'll then get a guilty feeling for running up electricity bills as it will no doubt need to run for a wee bit.
Saying that, if it helps dry the room out quicker than that can only be good - window is open and the extraction fan is going for it as well, but it doesn't seem to make much difference, so worth giving a dehumidifier a try.
We had a similar problem, to the extent that we were getting damp walls in the rest of the house. Hugely improved by fitting a fan with a constant low level trickle as well as a humidistat - it comes on once things start steaming up and remains on until everything has cleared, although I would generally try to give it a helping hand by opening the window. The problem was of course eventually solved completely by the kids growing up and moving out…
Might look at a dehumidifier but suspect I’ll then get a guilty feeling for running up electricity bills as it will no doubt need to run for a wee bit.
5p for an hour after showers is worth it.
I fitted a humidistat fan too, xpelair one that was about £60.
Have it on a low timer and slower fan speed so can barely hear it on the middle-of-the-night toilet visits. After a shower it just stays on for as long as it needs to until the humidity drops again.
Lots of replies thank you but...
Can’t your offspring split their washing and preening regimes between some of your other bathrooms?
We just have the one other (our en-suite) – the house isn't that big unfortunately! We do try to get them to split, but two of them (twin daughters) both play netball for the same teams so they usually want to shower straight after. We do try our best!
They don't like having the window open in winter (I can't blame them, I hate it too).
I think the setting is on the highest power - I am sure I have checked in the past but may do so again (and whilst I am up there, change the run-on to maximum (although we do usually keep the lights on after they have finished.
We always get them to open the window wide when they are finished.
And we do have a dehumidifier, but that gets moved around a bit as we also use it to do some clothes-drying duties too.
The cold air hits the fully saturated hot air in the bathroom & all of the water condenses on the walls & ceiling. If you keep the window shut & let the extractor do its thing, then it removes the saturated air, before the water condenses out.
Interesting – I hadn't considered that.
if you place your hand close and if you put a sheet of loo paper near the vent, it gets sucked into the opening
Yep I have tried that several times (when I start to wonder if the thing is working at all)!
The cold air hits the fully saturated hot air in the bathroom & all of the water condenses on the walls & ceiling. If you keep the window shut & let the extractor do its thing, then it removes the saturated air, before the water condenses out.
Interesting, I hadn't considered that, but it makes a lot of sense. Learn something new every day - and may also account for something going on in our bathroom 🤔
Window. Just replace the air. Then close the window an hour after they are done. Works in our house.
The cold air hits the fully saturated hot air in the bathroom & all of the water condenses on the walls & ceiling. If you keep the window shut & let the extractor do its thing, then it removes the saturated air, before the water condenses out.
Before I suggest this and the entire family questions my sanity, is there anything anywhere to back this theory up?
is there anything anywhere to back this theory up?
The laws of thermodynamics, mainly. 🙂
It makes perfect sense, it's just that most people are attached the the idea of 'fresh air', because it feels less humid. Which it is, because it has dumped its moisture over the nearest cold surface. Opening a window in cold temps only works if there is something driving warm moist air out of the window, like a through-breeze. If you're in a room with a powerful extractor chugging away, air will mostly be entering rather than leaving via the window, dropping the overall temperature and increasing the amount of condensation.
We used to get around this by having lots of airbricks shunting freezing air continuously through bathrooms, and by having lots of other cold, unpleasant draughts.
id also like an answer to the window + manrose issue please.
i tell my wife that its one or the other, either open the window and let the steam out, or keep the window closed and let the fan expel the steam (also have the same 'stepped' issue tho into the roof before it steps back down to the soffit)
ive told her that if youre doing both (the fan is next to the window) then the fan will just be pulling in the outside air to expel rather than the steam in the room.
is that right?
Hooray for not opening the window in Winter! 🙂
I sometimes squeegee that tiles in the shower to save it adding to the task.
The cold air hits the fully saturated hot air in the bathroom & all of the water condenses on the walls & ceiling. If you keep the window shut & let the extractor do its thing, then it removes the saturated air, before the water condenses out.
It makes sense, but we have one bathroom, no fan, and leaving the window open for a bit has never once failed to completely clear it of condensation. Even on the recent cold damp evenings after my partner's spent half an hour in the shower.
Don't overthink it.
Similar setup here (2 teenage boys, Manrose silent extractor in the ceiling, although it's 2.5-ishx4m), but no problems. Following on from others - main difference I think (or could be) is ours is recent extension and well insulated, so the walls etc aren't too cold - the hot steamy air condensing on cold surfaces is your enemy. I don't think our extractor pulls that hard, but it's enough, so extraction isn't the whole story.
Obviously that doesn't help you directly, but I'd say Dick and Stumpy are on the right track here - maybe look at keeping it a bit warmer + insulation if possible? Also of course look at the airflow (which you do indeed imply in your post) - if air is just pulled in at the door then up the vent that doesn't do anything for the steamy shower air.
And re the cold air theory - cold air definitely holds less moisture, so once it's mixed with (probably) saturated warm air that excess moisture has to go somewhere, so I'd say Stumpy may have a point. Depends really if/how it mixes, which will vary per bathroom window configuration no doubt.
Same fan and bathroom size, just one teenager with very long hair and I have the same issues. Old house makes it worse. If I have one of my morning showers there is no condensation at all but if I go in after the daughter it steams up.
I have my fan set on a seperate switch to the light so leave it on quite a bit.
As said above heating the room before the showers makes a big difference. Try blasting a fan heater through the ajar door to warm it up as an experiment. It won't completely solve the problem as those long showers will win.
I've just installed some extension pieces of glass so the shower enclosure goes all the way up to the ceiling. The fan does a really good job of sucking the steam straight out (100mm inline), and nothing escapes into the room other than for a second when getting out the shower. With the enclosure door closed, you can see the air being drawn in around the edges. It's taken a lot of DIY fiddling, some alumium extrusions and two fairly large, heavy and expensive pieces of toughened glass, but well worth the effort.
The inside of the shower is going to be very much wetter and probably need a plastic ceiling as the paint will be saturated, but the rest of the room is dry and we can leave the bathroom door open now so better circulation generally.
What about a more powerful extractor with greater extraction rate? And increase/improve your ducting at the same time?
https://www.screwfix.com/p/xpelair-ximx150t-6-axial-inline-extractor-fan-with-timer-220-240v/5338p
^ over twice the extraction rate of your Manrose. We had an inline extractor mounted in the roofspace above the windowless ensuite in our last house - think it was the same Manrose MF100 you already have - and it coped fine with two adults showering no probs.
I like @Mowgli's approach of a 'sealed' shower cubicle with venting straight out though. Saving that idea for future bathroom plans.
This is it. The alu strips between the original glass and the extensions are 'H' profile, and there are 'U' profile ones screwed into the ceiling.
over twice the extraction rate of your Manrose.
That looked an interesting consideration and I was reading through the reviews on Screwfix and saw this...
The literature with the fan states a max flow of 400 m3/hr rather than the 565 stated in the item description.
This has put me off a bit – I am not sure it would actually make much difference for quite a hefty investment – and I would still have to step the ducting down from 6 inches to the 100mm x 54mm rectangular that I need to use to fit in the available extracting space under the eaves.
’ve just installed some extension pieces of glass so the shower enclosure goes all the way up to the ceiling.
does this make your shower much warmer?
does this make your shower much warmer?
And stepping back out *much* colder. I don't like shower enclosures for that reason.
I think you need 2 fans . A near silent , low watts , low volume unit that runs on a timer from say 0600 - 2200. Plus a noisy big high volume fan , with overrun timer set to 30 mins , slaved off the light switch.
Big fan deals with the high load whilst shower is in use and immediately afterwards. Small fan deals with the moisture coming off towels , drying surfaces etc
It will be a combination of steam from hot water plus the constant release of vapor from a drying towel that makes the bathroom damp and mouldy.
Dry air feels warmer and heats up faster.
It all depends if you have the ability to either shove one downstream of the existing one or fit another
We have a small bathroom without opening windows and a blauberg calm 100. Only 2 people having shortish showers though. We squeegee showers area after each shower and leave door closed and fan on for about 10 mins. That clears almost all moisture and then we open the bathroom door and leave it open but we have a piv installed in the house too so that helps push out moist air.
I bought a massive inline fan to solve this problem. Now it vibrates the **** out of my whole attic...
I fitted a fan with a humidistat, takes a while to clear condensation but it does work, is quiet, and uses very little power. Xpelair.
Similar sized bathroom to OP. 2 big extract fans here, one above the shower and one by the window. Both on max timer settings (25ish minutes). Sueegeeing down after each shower and window kept shut in the winter because physics. I took my fans apart and gave them a good clean a month or so ago. That improved things a lot. The crud buildup in one had stopped it turning which clearly wasn't helping.
The efficiency for the fan with regard to it's displacement per hour is also effected by the length and "straightness" of the exhaust duct. Each 90 deg bend is the equivalent of an extra metre of duct length. Keep it short and straight! Also check for condensation build up in the duct causing a water blockage like a u-bend. Ideally have the duct go straight up, then down a gentle but consistent gradient to the exit point through the soffit. Any condensation should naturally drain out.
EDIT: I am just re-doing the extraction on both of our bathrooms. I am relocating the vent to right above the showers, and fitting a humidistat too. The fans will not be on timers, they will run when humidity dictates. I am using insulated ducting or rigid piping. The ribbed flexi stuff needs to be installed as taught as possible for max efficiency.
Our bathrooms (8 year old new build) were built with air intakes too. This is essentially extractor fan ducting without the fan. These bring in colder drier air to replace the warmer humid air. The vents can be screwed closed if needed
See also: Windows
I bought a massive inline fan to solve this problem. Now it vibrates the **** out of my whole attic…
My brother has this too, well, he used to. When I stayed there last xmas and he moaned about it, I convinced him that we could fix it by making a harness out of inner tubes and a piece of wood. Next morning when we'd sobered up a little, we gave it a try, fan mounted on a wooden board, board hangs from above with 2 tubes and 2 tubes attached below the board for stability. No vibration at all now and still going almost a year later.
It's so good I might patent it, the hanging board rather than the thinking of solutions to problems when half way into a bottle of port 😉
Window vac shower screen, tiles, bath sides, shower tray, window, anything with moisture on few minutes after shower. Fast, easy and efficient, my walls are tiled so I do them as well. Never use the fan anymore.
Steam / vapour isnt the only water in the room after a shower - you can do a lot to reduce humidity even with just with a squeegee and clearing all the water droplets from the shower enclosure after a shower so that water drains rather than evaporates
It’s so good I might patent it, the hanging board rather than the thinking of solutions to problems when half way into a bottle of port 😉
I think the Covid Enquiry would be held up as 'prior art' if you tried to patent the bottle of port/problem solving thing.
I vacuum the tiles and screen with a hand held thing after a shower. This helps limit condensation around my home too. I don't have an extractor fan.
I've been battling this for years. No issue with getting rid of steam but water settles on the top notch paint (Dulux diamond jobby) and it cracks over a period.
Solution: paint in summer and use that zinsser stuff, let it dry properly before showering again
Winter is the issue and I think opening the windows despite clearing the room - actually causes more condensation on the walls.
So don't really open windows now and humidistat does it's thing. Same as others in here room is probably not warm enough on the walls.
Can't figure out the logic but opening windows causes more harm that good as you're letting cold air in.
rone
Winter is the issue and I think opening the windows despite clearing the room – actually causes more condensation on the walls.
So don’t really open windows now and humidistat does it’s thing. Same as others in here room is probably not warm enough on the walls.
Can’t figure out the logic but opening windows causes more harm that good as you’re letting cold air in.
Same experience here with opening a window on a cold day making it worse.
I've mentioned it above, but basically if you open the window the cold air rushes in & cools down the warm air in the bathroom. Cold air can't hold as much moisture as warm air, so all of the moisture in the previously warm air, has to go somewhere as it cools. So, it condenses on the walls.
If you allow the extraction to get rid of the damp air before opening a window you lessen (or prevent completely) this condensation effect, so the walls don't get as wet.
I have a downstairs bathroom with no window, and a similar shower arrangement to Mowgli's image, without the enclosed top
I'd argue that having an extractor fan in the ceiling is not the best location as water vapour is quite dense and settles. I have an extractor fan in the wall venting outside.
Heated floors.
For when it gets really moist I've got a small desk fan standing on the corner of the 'top', and that makes a big difference clearing humidity
We have a shower room downstairs and seemed to have a lot of condensation/humidity and mould problems with it - the shower does chuck out a lot of water, the fan is not that great and there are no windows. Old house with cold stone walls.
I have a dehunidifier outside the door, but the real improvements came when I put a small squeegee on the wall (OXO Good grips) on the wall and after a shower sweep the walls down into the shower tray and then the water in the shower tray into the plug, and then later run the towel over the walls to remove the last of the moisture, plus any on the floor.
The towel then goes in the wash bin, although because of the squeegee it is much less wet than if it were used to wipe the walls down on its own. Obviously we go through towels at a rate but the washing machine has an efficient quick cycle and the tumble dryer is also quite efficient.
The fan is then enough to remove the mist in the air whilst I am finishing up shaving/etc.
The mould in particular is gone/reduced massively.
I note your fancy tiles make sweeping them down with a squeeee slightly less easy.
(I tried my karcher vacuum but it was just a pain in the backside).
Our bathroom has a solid brick external wall (Victorian House). We just leave the window open after showers and then close it an hour or so later once the walls are dry.
Room goes from soaking wet to bone dry in an hour or so even in the depths of winter.
OP hasn't replied on how the fan is controlled. Bathroom fans really need to be driven by a humidistat rather than just timer.
and as others have said, you need to heat the room as well.
Ideally, heat recovery ventilation for that room so constant ventilation without losing the heat.
https://www.bpcventilation.com/heat-recovery/heat-recovery-fans
OP hasn’t replied on how the fan is controlled.
I did, albeit in a pretty rubbish way so may have been missed - it's just on a run-on timer but I usually just leave the lights on too so it keeps running anyway.
Unfortunately, I don't really have the £££s to be buying lots of stuff to fix it – I was looking for techniques to minimise the effects really. I will be getting the kids to try the 'keep the window closed' technique to start with and see how that goes. I don't really have a way of heating the room other than the centrally-heated towel rail – but that is very powerful and does actually kick out a noticeable heat. The room itself is reasonably insulated – it's a modern (well, 1980s) house, brick-built with cavity and loft insulation. Unfortunately the underfloor heating has broken – that's a task for when the bathroom gets redone, which won't be for a few years as we only did it about six years ago.
Bigger gap. Bigger fan. Longer run time. Shorter showers.
Edit.
Unfortunately the underfloor heating has broken
Oh. That’s a pain. It makes a BIG difference.
Consider opening the window as in the absence of a bigger fan and bigger gap it will help. While also increasing your energy wastage and making the teens moan ‘why is our bathroom cold’.
2 kids, one nearly 22 other 18. Shower gets hammered every night.
Got a decent Manrose extractor that does it's best but it's a losing battle. I also have a good dehumidifier with a Tapo smart socket that's on a timer, or I just flick it on from my phone. Not ideal but works.
You can get a data logging rh monitor from Amazon for a tenner. It will show you how long it takes for rh to return to normal with either fan on or window open. The standard crappy fans can take several hours not the normal 5 minute over run. As above squeegee everything after showers. That is a lot of water that evaporates for hours after your shower soaking the walls. Humidity controlled fan, 10 mm gap under door, rigid insulated ductwork with minimum bends or straight through wall. No crushed and curled up flexi duct in loft spaces.
Re Opening the window.
I think that the efficiency of the air extraction is dependent on wind direction.
A flank wall with the wind blowing more or less straight at it isn't going to extract the air at all.
You need airflow along the side of the house to create a neg pressure in the room , to draw out the air.
Obviously redirecting the wind isn't possible, so sometimes it might be necessary to open a window on the wrong side and leave the bathroom door open. The drawback is the moisture laden air has to go further, and you have to have a window open in say , the lounge or bedroom all day . However, ime a dry house heats up very quickly once you close the windows and fire up the ch
Window after the shower - if a quick changeover, leave the window and door open at the same time for a couple of minutes. Most of the warm, humid air will leave the house. The air isn't the expensive bit to heat, it's the solid stuff so you won't lose that much energy.