Bathroom window open with extractor fan on? 7 October 2013 at 9:22PM in In my home (includes DIY) MoneySaving 20 replies 33.4K views

Itsgottabedone

Could anyone tell me whether an extractor fan will work more effectively with bathroom window open or closed? (I don't want to use more electricity than necessary, and also want to clear the post-shower moisture from the room as soon as possible. I realise these two aims may not be possible to achieve simultaneously!)

Jonesya

I'd have thought that having the window open will help clear the moisture more quickly and it'll help the fan very slightly as there's less restriction. Possible downside is that you lose the negative pressure in the bathroom, so more moisture/smells etc might blow under the door back into the house.

I'd forget the electricity though, little fans only use a few tens of watts and the difference will be minimal, fractions of a penny per hour.

Melaniep101

I always open the window to clear the steam quicker...

butler_helen

Melaniep101 wrote: »

I always open the window to clear the steam quicker...

Same here and it is a noticeable difference to having just the extractor.

katejo

butler_helen wrote: »

Same here and it is a noticeable difference to having just the extractor.

I agree. My bathroom window stays open a lot of the time.

Itsgottabedone

A consensus to continue what I'm doing, then! Thanks, all.

lstar337

Your best option is to also have the window open while the steam is being produced. So open it before you have a shower/bath to let the steam out before it has a chance to settle on walls etc.

evoke

Yep, definitely open for as long as the extractor fan is operating.

cyclonebri1

It's not a definite at all I'm afraid. Think about it

It's all down to where the extractor is in relation to the window.

If you have a 10 ft long bathroom with the window 3 or 4 feet from the fan, what's going to happen?

The air will be pulled from the window and take a shortcut or short circuit up the extractor, Air at the far end doesn't get changed.

I can quote my own situation, bathroom 15 ft long and mostly quite narrow. Extractor over shower, only window is to the side about 5ft away. Opening window doesn't work, the mirror at the other end over the sink will not clear.
The answer in my case is either to shut the window and interestingly watch the air being drawn down from around the flush mounted ceiling lights, (the mist swirls below, you can see what's happening). Or, open the door which is at the far end from the shower, this clears the room fastest, but I do that dependant on season.

lstar337

cyclonebri1 wrote: »

It's not a definite at all I'm afraid. Think about it

It's all down to where the extractor is in relation to the window.

If you have a 10 ft long bathroom with the window 3 or 4 feet from the fan, what's going to happen?

The air will be pulled from the window and take a shortcut or short circuit up the extractor, Air at the far end doesn't get changed.

I can quote my own situation, bathroom 15 ft long and mostly quite narrow. Extractor over shower, only window is to the side about 5ft away. Opening window doesn't work, the mirror at the other end over the sink will not clear.
The answer in my case is either to shut the window and interestingly watch the air being drawn down from around the flush mounted ceiling lights, (the mist swirls below, you can see what's happening). Or, open the door which is at the far end from the shower, this clears the room fastest, but I do that dependant on season.

Yes, it is going to be room/situation dependant. Best thing to do is experiment.

If I leave the job to my extractor fan, it'll take all day. In fact, using the window alone is far better at clearing the moisture than anything else.

Our extractor is wired into the light, so it's not really possible to not use it, but I always use the window to speed up the process.

penguingirl

We have a humidistat fan and it def switches itself off much quicker when the window is open