Extractor fan installation - do humidistat fans work well?

elsmandino

Thank you.

Rather oddly, just like desthemoaner, my house is also a bungalow and had no extractor at all until recently.

I completely agree about being realistic - my house is, unfortunately, naturally very damp.

I bought a really good dehumidifier a few years ago (Meaco 25L) and tend to run that during the winter months.  I tend to run it overnight, to keep things at 60%, if possible.  I am trying to not run it during the day, as the current cost of electricity is a bit of a factor.

As you say, humidity may well be constantly over the minimum 60% threshold.

At the moment, I have set it to 90% (which I did at about 7pm yesterday) and it has been on ever since.

The thing about this particular brand of extractor fan is that the manual confirms that you must not change the humidistat dial while the fan has power - this is a bit of a shame as I could have otherwise bought a humidity sensor and manually changed the dial until it just kicks in/turns off.

Also, it takes 48 hours for the fan to adjust to every change you make to the humidistat - going to be quite arduous to get the thing up and running correctly.

Whilst it could be a fault with the fan itself, I suppose it could be the way that it has been installed.

My bathroom had a large wooden vented slat on the wall with an airbrick on the other side, which was meant to provide ventilation but was ultimately hopeless.  My electrician pulled the slat off, plastered up the hole and installed the fan there - I am wondering whether doing that is somehow causing the fan to sense constant humidity.

Eldi_Dos

@elsmandino,  Hi bit of a bump I know but could you share how effective the new fan has been in controlling the humidity in bathroom. Did you get a setting that worked for your situation ?

badatDIY

Have you got loft access above the bathroom? Inline fans tend to be much more powerful than axial fans (the ones you put through the wall) and because they are located in the loft can often be quieter (often but not always - installation and the specific fan matters). This website has a good calculator for what size fan you will need: https://www.tlc-direct.co.uk/Technical/Ventilation/Ventilation4.html.

Rather than a humidistat you could hook it up to some sort of motion sensor that activates it when someone goes into the bathroom.

The other thing to do if you don't go for a humidistat model is get one with a run-on timer. Also if you work out the volume of your room and then look at the volume a fan extracts (bearing in mind the numbers quoted are with no ducting, so reduce it a bit) you can work out how long you need the timer to run on for. You probably need about 4 complete air changes after a shower, for example, to really ensure the moisture has been sucked out.

Madmart100

My experience with my bathroom extractor fan -Intervent BVF100H (Manrose Rebadge?) is that the design of the actual sensor means the operation is a bit sporadic and not necessarily just due to the conditions in the bathroom. It’s probably a bit basic relying on moisture between the 2 electrodes. Whether the conductors sit on a certain material I’m not sure. So after going through the initial period of not wanting to switch off it has now, after a year, gone to not wanting to switch on. After firing steam at the sensor it activates probably well over 100% and then eventually dries out to never come on again-which makes me think there must be some certain material the sensor electrodes sit on? After a lot of searching I’ve found someone who sells the sensor (Cybersen Sensor) for a lot less than a new fan. He even states about the problem of  faulty sensors causing fans to run permanently or not at all. To save major dismantling I will snip off the old one and solder the new one to the remaining wire legs-with all the power FULLY off of course!

Madmart100

Update: My new Cybersen Sensor didn’t last long and so I’ve just purchased an alternative brand from EBay. 10 for about £6. I’ve also purchased some tiny 2 pin sockets off RS as all the soldering didn’t do the printed circuit board any good. Works great. Now I can easily plug a new one in each (year?).