Bathroom ventilation fan

droopsnoot

ThisIsWeird said:

droopsnoot said:

The bathroom and garage do run side-by-side for the full length of the bathroom, and in fact the garage sticks out a few feet in front and forms the side wall of the porch. By the time we're at the back of the garage the roof has sloped down quite a distance, and it'd be at least 12-15" below ceiling height to get the fan to vent into the garage. If I run the ducting below the roof support beams in the back of the garage, it would be pretty low unless I do some sort of flattened ducting. I also have some water pipes around there - the boiler is in the garage, so I have flow and return to the hot water cylinder, and the same for the radiators. 

I could install it at the front of the bathroom, but then I'm back to having a grille on the front of the house, which if you recall from my post is something that I'm trying to avoid if I can, or a complex job to make it escape via the soffits because there's less room to work.

We need some pics!

You can do a lot with flat, rectangular ducting, like: https://www.screwfix.com/p/manrose-204-x-60mm-flat-channel-1m/59769

So, you can try and work out how to run this in between the garage joists, or - if it must fit on them - it won't stick down by more than 2". The fan itself can certainly be mounted in between joists, so not stick down any further.

It's quite a tricky area to get photos of, unfortunately, and also quite tricky to draw, especially when you have my drawing skills.

Reading what people have said, it seems that the most effective way is to find somewhere to put it at the front of the room, perhaps block off the air brick (it was blocked until recently, I opened it up to see if the natural ventilation would help, and it doesn't) so that the replacement air comes from the house. It's just a case of finding an exit route that I'm prepared to put up with.

ashe

Ask a roofer what your roof tiles are. You can get universal fit tiles although not as good as a proper fit I don't think, but my friend had to get one put in as his tiles are no longer made

Emmia

droopsnoot said:

ic said:

It looks like your roof is easily accessed from the roof of the garage.  What about a ceiling fan above the shower, venting out of the roof or soffit?  Whatever you get, make sure it has a humidistat so it keeps running until the room is cleared.

Someone mentioned a humidistat, I had just been thinking of a fan with a run-on timer or maybe even just a fan that runs while the light is on.

I would definitely get a fan with a humidstat rather than one that only runs when the light is on, or when the fan is activated manually or a fan with a run on timer. 

The humidstat will ensure the fan runs (at a low level) when the moisture level/humidity is over a certain level - even if the light is off or the shower isn't in use. (Yes, they do come on at 3am if the moisture level warrants it)

We have windowless bathrooms where mould was a major problem when there were fans that relied on overrun timers. When one broke, and the other started sounding like it was on the way out we got both replaced with humidstat versions - the fans probably ran continuously for 48hours when they first went in (which may indicate the level of dampness) and the humidity level in the flat dropped by 20% in the first week. Yes, they weren't the cheapest fans (I did pick quiet ones though) but after they went in I treated the mould and it hasn't returned (and it would regularly return before those fans were installed). 

You're going to spend some time /energy / money sorting out the ducting, get really good fans as well to fix it properly.

droopsnoot

Thanks for the additional notes, I've been thinking about possible routes outwards and I suspect I may find some sort of chimney to fit into the garage roof. That gives me an easy route outwards, without having something unsightly on the front of the house, and if I paint the thing black it will hardly be visible. I did have a look at tiles with vents in them, but I'm back to having the fan in a spot that's pretty difficult to access if or when it goes wrong at some point.

droopsnoot

Going back to the humidistat, where does it actually sit? Is it in the fan unit, or in the grille, or somewhere else?

I'm looking at a grille on the bathroom wall, ducting through the wall to an inline fan mounted in the garage, then a further duct to an outlet on the garage roof somewhere. Fan will be next to the consumer unit so wiring is easy, and it'll be accessible if I need to replace it, and any noise won't be so obvious inside the house.

Presuming the humidistat is inside the fan unit, will it still sense the moisture in the air in the bathroom? Or would it be better to have the fan mounted directly in the bathroom wall and a single duct from there to the outlet, and hopefully run the power cable through the same hole alongside the duct.

I'm browsing various online catalogues for this stuff and there isn't a lot of detail.

Emmia

droopsnoot said:

Going back to the humidistat, where does it actually sit? Is it in the fan unit, or in the grille, or somewhere else?

I'm looking at a grille on the bathroom wall, ducting through the wall to an inline fan mounted in the garage, then a further duct to an outlet on the garage roof somewhere. Fan will be next to the consumer unit so wiring is easy, and it'll be accessible if I need to replace it, and any noise won't be so obvious inside the house.

Presuming the humidistat is inside the fan unit, will it still sense the moisture in the air in the bathroom? Or would it be better to have the fan mounted directly in the bathroom wall and a single duct from there to the outlet, and hopefully run the power cable through the same hole alongside the duct.

I'm browsing various online catalogues for this stuff and there isn't a lot of detail.

The humidstat is in the fan itself, in the bit which would be behind the grille/fascia panel - it will sense the moisture in the bathroom, and turn the fan on automatically if the moisture level goes over a certain level. The one we have does this on low power (quieter) if the light is off. 

If linked to the lighting, when the light is switched on when the bathroom is in use, the fan works on  full power, which continues for 10mins after the light is turned off - the fan then drops to low power if necessary, or turns off (depending on the remaining humidity)

Our fan is mounted on the bathroom wall, with ducting going to the outside, where the moisture is extracted to.

droopsnoot

Ah, so if I use an inline fan that would put the stat a bit further away, and perhaps make it less effective. Thanks.

Emmia

In case the OP is interested, I think we have this one (or perhaps an earlier model) 

https://www.screwfix.com/p/vent-axia-479087-100mm-4-axial-bathroom-extractor-fan-with-humidistat-timer-white-240v/617gy