Bathroom extractor fan

Rachbuka

Hi all, 

we have a bathroom extractor fan that is linked to the light and so it turns on automatically when we switch on the light and it switches off on a timer (I’d say about 45min). 

It can also be switched on and off manually on the wall. 

I was wondering what is the most proficient way of using it. Is it better to turn it on and off manually or is it better to leave it on the automatic mode. 

I’m thinking energy costs and humidity levels. 

Thanks in advance for any advice! 

Jeepers_Creepers

You'll almost certainly find that the timer duration is adjustable, so if it's really 45 minutes - that's a hell of a long time - then you may wish to knock that back to 5 or so. Is it a noise nuisance at night, for example?

I personally think that automatic switching with the light is nuts. Having the fan come on every time you just want a pee is crazy.

So two obvious solutions, I'd suggest; one is to knock the time back to 5 minutes and ensure that this works whenever it's turned on manually. And shoot anyone who uses the loo for a shower, bath or No2 without turning the fan on. The other solution would be to add a humidistat sensor type which will automatically come on - and stay on - until the humidity levels from a shower etc is reduced right down. This should also have a manual override, tho', as No 2s don't trigger it.

So, ideal setup - I think - would be a fan with a humidistat to automatically take care of condensation levels (ie, it'll run until the room is 'dry') coupled with a manual switch with a 5 minute timer (which should handle smells...)

So, nocturnal visits should pass quietly - unless your No1s are very steamy. Just saying...

Energy costs will be minimal, but a 45 minute run is nuts - surely noisy, and will certainly reduce the life of the fan.

Racky_Roo

Knocking it back to 5 mins won't be sufficient if someone has a shower. that wouldn't even cover the showing time, let alone the steam and moisture which needs clearing after the shower. Personally i'd change the time to 30 mins and have it left off and just turn it on when going to have a shower. It'll then overrun when you finish showering until the 30 mins are off and you just turn it off later on.

Le_Kirk

The timing (overrun) starts when you turn off the light, not when you finish showering.

tacpot12

I have the extractor fans in the bathrooms of my rental property and my home wired as per Jeepers_Creepers' ideal setup suggestion. It works very well. 

I use the MS Electronics E925 Humidistats which have been completely reliable after 5-6 years. 

fenwick458

problem with a humidistat fan is they often run all day when it's humid or raining outside. probably avoidable if you get the duct type selection just right, and exit the duct out the building in a particular way but realistically who has the options to do that?
only time I ever got a humidistat setup working was by using a remote humidistat.

my personal preference with fans is have them come on with the light, and a short 3 minute over run. and then after a long shower on a cold day just leave the light on for an hour

tacpot12

I do find that my humistat controlled fans run occasionally when the outdoor humidity is high, but it is very rare that this happens. The E925 humidistat is a remote humidistat that is fitted over the bath, but not directly over the shower. The duct has a non-return valve in it which helps prevent moist air coming into the bathroom via the duct. The duct terminal in the bathroom is situated over the shower area in the bath, so about 0.7m away from the humidistat which also helps reduce the  operation of the fan when the source of the humidity is outside. 

The duct fan I have fitted is very efficient. It draws about 20w on the low speed setting I have it on, so even if it occassionally runs when it should not, it always runs when it needs to and consumes very little power overall.