Bathroom fan with humidistat, plus manual control, plus more?

[JoeA]

We are having a bathroom refurb and I want to have a humidistat controlled in-line fan in the loft. I also want a separate switch that allows the fan to be manually turned on if required, so bypassing the humidistat control. Is this possible?
(We don't want the fan to be connected to the light switch in any way.)

I was planning on this fan: https://www.tlc-direct.co.uk/Products/SLTD250SILENTslashT.html
As it has a run on timer built in that could be useful to use within the system.

I was initially planning on getting this remote humidistat: https://mselectronics.co.uk/product/remote-bathroom-fan-humidity-control/
But the manufacturer has just told me they are having component supply issues, so there wont be any for at least 2 months.

So I have switched to this one: https://www.screwfix.com/p/manrose-1361-remote-bathroom-fan-humidity-control-with-timer/44376
With the idea to perhaps swap to the much better looking MS Electronics one once it becomes available. This Manrose 1361 also had a run on timer which is duplication because the fan has one too, but since the MS Elec humidistat doesn't have a run on timer, I wanted to design the system to use the run on timer on the fan only.

This is idea 1 - does that all initially sound possible?

I was also doing further research into the pitfalls of using humidistats to control bathroom fans, and it seems to be the case that the humidity in a bathroom can swing quite wildly to extremes during the shower and post shower phase. So I was thinking perhaps it might be possible to create a system that triggered the fan the first time the humidistat read a high humidity (i.e when the shower goes on) - but then disregarded the reading from the humidistat for a set amount of time to ensure the fan wasn't constantly cycling on and off which I've heard can sometime be a problem? This is idea 1A!

Is idea 1A possible? Or would it make more sense to just stick with the simpler idea 1.

I am doing this because my kids will never remember to manually turn on the extractor fan, and are starting to take longer and longer showers!

Many thanks

 

[jj4091]

Keep it simple. Independant switch with run on timer fan.

 

[mikehammer69]

I automated mine so it comes on when shower heater tank draws current

Easy done if fan is wired from box.

 

[Murdochcat]

Humid stat fans are the work of the devil - don’t bother with one. Decent inline fan with over run time is a far better solution

 

[flameport]

and I want to have a humidistat controlled in-line fan in the loft.

You may want one now, but you certainly won't want it after it's been installed. It will require constant adjustment to work properly some of the time, the usual modes are the extractor never working, or remaining on permanently.

Even if it could be made to work, humidity is a poor choice, as ventilation is required for other reasons.

I am doing this because my kids will never remember to manually turn on the extractor fan,

PIR sensor in the ceiling so it turns on when people enter the room. Those have a timer in them, so the fan won't need one.

 

[JoeA]

Thanks for all the replies. In some corners of the Internet there appear to be some people using humidistats perfectly happily, and obviously lots more who say they don't work properly. I'm just wondering why they seem to work just fine for these select few.

PIR sensor not ideal as don't need fan to come on ever time someone goes into the bathroom.

One other idea I had was to link a pipe thermostat on the shower hot feed to the fan, but that would then not turn on the fan for a hot steamy bath, so not my favourite.

 

[mikehammer69]

Doh ya I forgot mine was shower only

Needs to be automated anyway not manual control, manual switches can be left off

I think I’d be leaning towards PIR suggestion

 

[pete01]

PIR sensor not ideal as don't need fan to come on ever time someone goes into the bathroom.

It wont make a difference....mine comes on with the light, if I dont need the fan on it comes on anyway....doesn't bother me.

 

[jj4091]

I also want a separate switch that allows the fan to be manually turned on if required, so bypassing the humidistat control. Is this possible?


PIR sensor not ideal as don't need fan to come on ever time someone goes into the bathroom.

See post #2 On when you want it and runs on to clear steam when you switch it off on exiting the room

 

[mikehammer69]

See post #2 On when you want it and runs on to clear steam when you switch it off on exiting the room

The concern is if users decide not to turn on the main light

 

[JoeA]

See post #2 On when you want it and runs on to clear steam when you switch it off on exiting the room

Unfortunately my kids will be really bad at remembering to do that.