Bathroom lights and fan


(Conradj) #1

I’m getting our bathroom rewired and having an extractor fan installed - I would like it to:

  1. Automatically turn on the lights when someone walks in between sunset and 11pm, and turn them off after no movement in x minutes.
  2. Automatically turn on the lights at 20% when someone walks into the upstairs hallway between 11pm and sunrise, and turn them off after no movement in x minutes.
  3. Allow people to manually turn on the lights outside of these times.
  4. Control the extractor fan using similar rules.

I guess the best thing for the lights is a Fibaro in wall dimmer and motion sensors in bathroom and hallway, but what would you recommend for the extractor fan?


As long as you just need an on/off switch, not variable speed, any in wall micro relay that can handle the amperage of the extractor fan should be fine. These will, however, require a neutral wire. But if you’re having the wiring done now that shouldn’t be a problem.

There are several zwave brands available for the U.K., including fibaro

Just don’t get a dimmer version. Dimmers will be spec’d only for control of lighting, not for control of motor devices like fans. But as long as the device says it can handle appliances and it can handle the current draw for your particular fan you should be fine.

(Robin) #3

I use a fibaro 2x1.5kw micro module for my bathroom fan, went for the double relay over the single one simply because it costs the same as the single and the extra channel may come in handy one day if I want to add feature lights of something. 1.5kw is more than enough to run several fans so no need for the higher capacity 1x2.5kw version.

As @JDRoberts noted, these require a neutral.

My fan is triggered (restricted to sociable hours + 30 second delay for quick in and out events) by the bathroom lights turning on and I have a default 5 minute overrun timer programmed via webCoRE after the lights turn off again. I have the option using a button controller or double click on the light switch to increase the overrun time if required for those extra steamy showers.

This is the webCoRE piston I use:

(Conradj) #4

THANKS so much for that, really helpful. Few extra questions:

  1. Both you and @JDRoberts recommended the relay over the Double Switch 2 - how come? (sorry if this is a stupid question!)
  2. I hadn’t thought of triggering the fan from the lights like that, that’s cool. Is there a reason why you didn’t give the fan its own switch though?
  3. Is there anything you’d do differently?

Thanks again.

(Robin) #5
  1. Not really, the dbl or single switch options will also work. When I got the relay the switch options weren’t available yet. I do think the relays are more versatile for future repurposing though, as they can switch low voltage circuits as well.

  2. I have a Xiaomi button in the bathroom, high level just behind my glass shower screen but reachable from inside the shower by reaching over the screen, so if we don’t turn on the light we can still manually trigger (or turn off) the fan. We are not allowed wall switches inside bathrooms in the UK and I didn’t fancy having two pull cords which would confuse guests.

  3. I’m toying with the idea of utilising my bathroom humidity sensor to trigger the fan, monitoring peaks and troughs right now to find the best trigger points.
    Also, if wiring from scratch I would consider a fan isolator switch just outside the bathroom (high level over door) for those times the cloud is down and the fan gets stuck on.

(Conradj) #6

Yep, will have an isolator switch as described, and the light switch will be on the wall on the way in to the bathroom (and hopefully won’t need to be used much anyway).

Good idea to have a Xiaomi button in the bathroom for the fan, think I’ll do the same and forego having two switches as I can see it causing confusion. Do you have any issues with the first press not registering though?

Humidity sensor sounds interesting, but like you I’ll look into it afterwards. Thanks for your help!

(Robin) #7

Not yet :grimacing:

But I can always press it again if need be, wouldn’t bother me too much… and it doesn’t get used that often anyway as we usually shower early morning / late night so lights generally trigger the fan instead.

(Jon) #8

My piston for extractor fan is below. We always shower with light on as only have a small window in ensuite. So switching light on sets a humidity level above which fan goes on.

When light switches off fan stays on for 5 minutes which is long enough for humidity to be lowered

I have a xiaomi temp/humidity sensor in ensuite, fibaro dimmer module controlling lights and a fibaro relay on fan

(Robin) #9

You have the exact same 3 devices as I do in my bathroom lol.

(AB) #10

Can anyone help suggest a solution to try and make the light and fan smart? I have purchased a Fibaro FGS 212 Relay Switch and would like to control both the fan and light with it. I don’t mind about using a physical light switch and can leave this on all the time providing the fan and light and be turned off with the Fibaro. Thanks for any knowledge!

(Robin) #11

I responded to your identical post on another thread:


If I want to be able to dim the bathroom lights and control my fan will I need both Fibaro Double Switch 2 and Fibaro Dimmer 2?

Dimmer 2 behind the light switch, Double Switch in the loft connected to the fan?

After the lights have been on 1 minute the fan will come on until the lights are turned off.

How easy is it to set up the control of this, mainly the fan knowing when to come on?

(Robin) #13

Yeah, you’ll need both modules.

WebCoRE can sync the lights to the fan:

if light is on
Turn on fan
Wait 1 minute
turn off fan


Thank you, I will give that a try.


I need a very simple WebCore code.All I want is automatically switch off my closet light , 5 minutes after turn the light on
I not familiar with WebCore programming, can you please help ?

(Ron Talley) #16

If Light is On
Then with Light
Wait 5 Minutes
Turn Off

Some of my closets I have contacts
If Contact Changes to Open
Then with Light
Turn On
If Contact Changes to Close
Then with Light
Turn Off

Some of my closets I have motions
If Motion Changes to Active
Then with Light
Turn On
If Motion Changes to Inactive
Then with Light
Wait 2 Minutes
Turn Off

Some of my closets I have a combination of motion and contact
If Contact Changes to Open
Then with Light
Turn On
If Motion Stays Inactive for 5 Minutes
Contact is Open
Then with Light
Turn Off


This looks really great. But I have only little knowledge in writing code for WebCore. Can you please generate a screen capture which i can copy and paste and only change to my Switch names. Please… :pray: