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[obligatory "I used to be really into tractors, but not any more" gag]
I have an extractor fan in the bathroom ceiling. It is the only source(*) of ventilation aside from the door. It's inefficient and noisy to a point where despite my protestations my g/f keeps switching it off. I'd like to replace it.
It looks fairly simple, from the vantage point of the bathroom floor at least. There's a square grill covering a circular fan(**) maybe (eyballing) 200mm across? Can I assume this is a standard size? In the loft it's vented to the outside world via one of those corrugated pipe affairs leading to what looks like plastic drainpipe. It looks a bit of a bodge, truth be told. The fan starts when the bathroom light is switched on and runs on for a couple of minutes after the light is turned off, so I'm guessing the wiring little more than a neutral, a permanent live and a switched live.
I know nothing about these things. I have half a memory from a previous STW thread that there's different types, and a whole several seconds' worth of browsing in B&Q would suggest a bewildering array of choices. So, what do I need to know? Ideally I want something which is quiet, sufficiently powerful, and not going to cost me a kidney. Is this a "pick any two" scenario?
Thanks in advance.
(* - or I suppose, destination)
(** - as opposed to all those other shapes of fan)
Can I assume this is a standard size?
No, there are a couple of sizes. Remove it and measure the pipe that it fits into
so I’m guessing the wiring little more than a neutral, a permanent live and a switched live.
Yep. You might get an earth too
Ideally I want something which is quiet, sufficiently powerful, and not going to cost me a kidney. Is this a “pick any two” scenario?
It does seem a bit random whether or not they are actually quiet even though they all say that they are. We have an 'Xpelair' one that seems quite decent. Possibly the less powerful the quieter but then you trade off against airflow. I would see if they say what size of room they are recommended for
You might also find it you clean it if you get it down to measure it then it runs quieter
and of course switch off the electricity AND test to make sure there is nothing live, yadayada...
I've just done this twice.
It looks fairly simple, from the vantage point of the bathroom floor at least. There’s a square grill covering a circular fan(**) maybe (eyballing) 200mm across? Can I assume this is a standard size? In the loft it’s vented to the outside world via one of those corrugated pipe affairs leading to what looks like plastic drainpipe. It looks a bit of a bodge, truth be told. The fan starts when the bathroom light is switched on and runs on for a couple of minutes after the light is turned off, so I’m guessing the wiring little more than a neutral, a permanent live and a switched live.
This is pretty much bang on. No harder than wiring a plug.
The hardest bit was re-bodging the bodged extraction. Ours wasn't actually attached so it had been venting into a wall space for years.
They are all crap quality so ended up searching on noise levels as some are very noisy.
You need a Manrose inline fan - fit it in the loft. By the sounds of your set-up it should be dead easy assuming you can get to the wiring for the switch so you can (as you say) wire it up with a permanent and switched live.
We have a couple - they are *almost* silent in use.
*Technically* you should have an isolator switch to pass regs I believe, but who's to say it hasn't always been like that and you just fitted a replacement fan recently.
ooo, inline fan is a great idea
From experience, you may well be able to do something about the inefficiency and noisiness without replacing it.
Open it up and clean the blades, they're bound to be gummed up with years' worth of dust and towel fluff, which will make them both less efficient and vibrate more, so noisier. Clean the grill too.
Also, whether you replace it or not, if you're running it with the door closed, is there enough room around/under the door for air to enter the room to replace the air the fan is trying to suck out? If not, it won't work very well and will be noisier as it's working harder. So, might be worth sticking a vent in the door or just taking half an inch off the bottom.
No, there are a couple of sizes. Remove it and measure the pipe that it fits into
Alright. I haven't removed it but I've just been up in the loft with a ruler. The OD is 160mm.
Yeah, if you have the space & the access I would be going for an inline fan.
We've got an Aventa 100T - 100 as it's for 100mm ducting and T for timer. I am not sure if they do a version with a humidistat.
Get one to suit the diameter of ducting you already have in there.
Open it up and clean the blades, they’re bound to be gummed up with years’ worth of dust and towel fluff, which will make them both less efficient and vibrate more, so noisier. Clean the grill too.
I considered this, but if I'm going to go to the hassle of taking it to bits I figured I might as well fix it with a new one. Assuming it's not going to cripple me financially anyway.
Also, whether you replace it or not, if you’re running it with the door closed, is there enough room around/under the door for air to enter the room to replace the air the fan is trying to suck out? If not, might be worth sticking a vent in the door or just taking half an inch off the bottom.
No, and that's a good point.
The problem with the bathroom is that there are no external walls so no windows. The door is panelled so there's no elegant way of adding a vent (unless I added two I suppose?). I hadn't thought of planing down the bottom, though that might turn into catnip for inquisitive paws (the reason we have to close the door when in the shower / bath).
What's an inline fan and what's it instead of?
Do I take out the old fan, plumb the duct directly onto the hole, then cut it further along the pipework to install the inline version? What's that gaining me?
Ooh! I think this is exactly what is fitted currently:
We are currently redoing our bathrooms and I bought a couple of Silent Tornados:
https://www.gil-lec.co.uk/silent-tornado-st100t-bathroom-extractor-fan-timer
Link to the version with a timer like your current one but there are several options.
Not the cheapest but I went with the thinking that I wanted to buy something a) quiet and b) good quality, to fit and then forget about for many years.
Apparently (according to them) this is the most quietest and most, um, air-suckiest fan on the market. Can't comment on actual usage as it's still in the box 😁
I'm going through this at the moment.
Not sure of your duct length but if it's going through a loft it's most certainly too long for most axial fans, so as suggested an in line fan could be a good option, or alternatively a centrifugal fan. You might need to check with the manufacturer on exact duct run lengths, some centrifugal I've looked at have been good for up to 10m duct lengths, some less.
Also you might need to consider a condensation trap, there are generally recommended if the duct is going through an uninsulated space where the warm air will start to condense and run back down the duct.
The door is panelled so there’s no elegant way of adding a vent (unless I added two I suppose?)
You can get long thin vents that should fit in the bottom bit below the panels (less ugly ones probably available):
What’s an inline fan and what’s it instead of?
Axial fan - the fan unit sits in the hole in the ceiling (although they're really for holes in walls where there's little distance between inlet and outlet)
Inline fan - there's ducting from the hole in the ceiling to the fan, which is typically in the loft, and then from the fan to the outlet hole. Better for ceiling fans where there's more distance to cover between the inlet and outlet.
Our bathroom fans have humidity sensors in, so the overrun is controlled by the humidity in the room, rather than a set time. I've also fitted a smart switch in line, which is set to turn off between 11pm and 6.30am, so turning the bathroom light on at night doesn't start the fan.
Cougar
What’s an inline fan and what’s it instead of?Do I take out the old fan, plumb the duct directly onto the hole, then cut it further along the pipework to install the inline version? What’s that gaining me?
Your installation description is pretty much it. You would generally have a duct fascia of some sort on the ceiling connected to a run of pipe, then the inline fan goes in the split you make in the pipe run.
What's that gaining me?
Axial fans aren't very good at pushing against resistance. Long duct runs provide a lot of resistance and if you have no gaps for fresh air to get in, that equals lots more resistance.
An inline fan (or a centrifugal fan) can generate more pressure to combat resistance of the ducting etc.
Regarding the gap in the door. More is better, but if you can take of 5mm that would be good. It could be that your current fan isn't actually providing any flow as there is no fresh air coming in to replace the air that the fan is trying to remove.
We have about a 5mm gap under our door and if you stand with your bare feet next to the door when you turn the light (and fan) on, you can feel the draught it generates as it pulls fresh air in under the door.
Mounted directly on the joists it was a bit noisy, but I bought some vibration isolating feet from ebay or amazon & all the vibration through the joists has been virtually eliminated. It would be even quieter if I'd swapped hte flexible ducting for solid pipe runs.
The problem with the bathroom is that there are no external walls so no windows. The door is panelled so there’s no elegant way of adding a vent (unless I added two I suppose?).
Just trim the bottom of the door (or check if it would benefit from being trimmed) - the 'vent' at the door doesnt need to let more air through than the fan is drawing - so just having a half inch gap across the width of the the bottom of the door gives more or less the same amount of opening for air to flow through as the 150mm dia pipe the fan is feeding into
We used to have this fan in our old house - centrifugal.
It doesn't looks particularly elegant as the box bit sits on the ceiling, but it provides a lot of oomph and works very well.
I've added a "Shelley Plus 1" Smart Switch/Relay in between the Isolator switch and fan for each one in my house.
Means I can control them with Alexa/Google/Homekit/etc and have a routine that has them active for a set time each morning & evening.
Means they're not running for 20 minutes after my girlfriend has the light on to just goes to check her makeup/etc. But I can have them on or off anytime with a simple voice request
Not sure of your duct length but if it’s going through a loft it’s most certainly too long for most axial fans
I didn't know that was a thing. It's maybe 5m in total?
Also you might need to consider a condensation trap, there are generally recommended if the duct is going through an uninsulated space where the warm air will start to condense and run back down the duct.
Funny you should say that, guess what happened when the temperatures were sub-zero a few weeks back.
What's that look like? I'm not being particularly fruitful on Screwfix.
I'm liking the smart switch idea, and that's probably an easy win because the isolator is a switch on the wall next to the light switch. I suspect there's a neutral wire in there too, somewhat unusually all the light switches (that I've checked) have it present. But for now that's going onto the "phase 2" list.
Each one is small enough to hide inside a std depth switchbox behind each isolator switch 🙂
https://shellystore.co.uk/product/shelly-plus-1/
Great little things that can be added to make almost "anything" smart controllable
I'm familiar with Shelly's work. (Shelley, less so.😁)
Xpelair here too. The wiring in some of our fittings, particularly lights, is bonkers, so I took photos when removing the fan to ensure I could reverse fit the new one. Worked great for 3 years then stopped spinning up. Bought another one and that's been fine for a year or so.
I considered this, but if I’m going to go to the hassle of taking it to bits I figured I might as well fix it with a new one. Assuming it’s not going to cripple me financially anyway.
You don't need to. Turn it off, pop the cover off, and give it a good brush/ vacuum. Literally a 5 minute job.
I had to do this on mine, the accumulated damp dust had started to jam the blades.
What’s that look like? I’m not being particularly fruitful on Screwfix.
One of these.
https://www.toolstation.com/extractor-fan-condensation-trap-with-overflow/p73185
You don’t need to. Turn it off, pop the cover off, and give it a good brush/ vacuum. Literally a 5 minute job.
OK, cool, I'll give that a go. Ta.
One of these.
Ah, I was looking for some sort of filter. So, what, that's installed vertically above the fan? Wouldn't the drain need somewhere to, uh, drain?
I have 4 of these - Greenwood Airvac CV2GIP - they are great have humidstat so can be used continuously and still boosted when light goes on. Last one i picked up on ebay for £60
Havent read all the responses - you'll need 4 connections if you want to use all the functionality, perm live, switched live, neutral and earth. If you are replacing like for like fan it should be a doddle. Inline fans will involve more faff and getting dirty and depending where it will be boards up / big hole in ceiling. Maybe if you have really bad condensation problems its worth it.
Screwfix sell insulated ducting which might help with condensation. My previous fan turned out to be full of mouldy water.
Ah, I was looking for some sort of filter. So, what, that’s installed vertically above the fan? Wouldn’t the drain need somewhere to, uh, drain?
Yes would need to go into drainage somewhere. Where depends on your exact setup, still debating where to put ours to, possibly soil pipe. I have seen a couple without drain, it just captures and evaporates from there, but that seems a bit of gamble that you wouldn't accumulate so much that it wouldn't over flow quicker than it evaporates.
I've just replaced the fan above the shower with this:-
Manrose QF100TX5CON Conceal X5 Zone 1 Quiet Extractor Fan 100mm with Timer (White)
It's pretty quiet.
Got a Greenwood something or other in the bog. It's way louder.
If you look online, the noise and volume of air should be listed
Obviously you want a larger dia.
I used to pay extra for a humidistat version but in my experience they are very hard to tune, so either never come on or be on all the time.
I find it best to set the timer quite long instead, they don't use a huge amount of energy.
If it's zone one you want the higher IPx5 rating, assuming 240v.
Noise is also going to depend, to some degree on what you screw it to.
Inline 100mm shower fan should suffice . With overun timer , I do like the idea of the fan being 'off' betwtixt midnight and 0700 to allow for the 0330 bathroom visit.
Ceiling vent , fan screwed to joist , ducting to move moist air away is what you need.
Humidistat are great when new but can go out of range over time .
Axial fan with 38db ish , and mounted on some sort of sound proofing and a timer is acheivable