Unique challenge - Need good/creative solution for controlling bathroom fan

When I bought a new house last year it had a feature that I knew I wasn't going to like, and I was right. All the bathrooms are connected to one big fan in the attic. It works, it's quiet, and...

it gets left on ALL the time. You can't hear it. It can be turned on by any one of the 5 switches connected to it, so if it's on at any switch, it just stays on.

Ideally it would have some kind of time limit that turns it off without stopping it from being turned back on from the switches.

In looking at the wiring I don't think that a single switch would control it. It's not "multi-way" wiring. It's more like single way wiring x5. I think it would require 5 separate smart switches. Not sure I want spend that much to control one fan, and I'm not sure how it work.

If I put in a smartplug or smartoutlet how would that work? I could program it to timeout if powered on too long, but there is no way for it to know when to turn back on.

The only solution I can think of is to put in a smart outlet/plug and just have it notify me if it runs too long and then I can manually act on it. I'd prefer a more automated solution.

The simplest method would be to use 5 timer switches to control the on time. An automation method would be to replaced one switch with a Lutron switch and 4 two button Picos.

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How about one motor-rated relay/switch at the fan, and motion sensors in each bathroom? Trigger the fan on with motion in any bathroom, with a turnoff 10-15 minutes after the last motion stops? Automation...no hands required!!!!!

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I use one of these. It’s for one fan and one switch in my home, but they support 3-way wiring. Assuming you are in the US or Canada.

For automating it, I took a bit of a different approach. I use an Insteon micro module, but there are Z-Wave micro modules that do the same. The module has a sense wire. Essentially the output from the timer that would normally drive the fan motor directly, instead just supplies 120v to the sense wire of the micro module. When it senses voltage, the module flops its state.

This has the advantage of the family not needing to learn anything different from the way it was before I automated it. So then I can turn the module on via my hub (based on humidity from a sensor), and off after the amount of time I desire follow the humidity that is within the range I want to maintain. I use @iharyadi β€˜s module downstairs for a reference humidity, and a Xiaomi temp/humidity/pressure sensor in the bathroom (but I’d recommend the Konke instead).

So I get the best of both worlds. Manual timer, or automation via humidity level. Since the timer turning on flip flops the module, you can also manually turn off the fan if you want when it has been turned on by automation. You just push the timer on and then off again and the fan is forced to turn off.

Hmm... yeah... before everyone goes off try this or that... How this is wired needs to be identified and KNOWN exactly before any solution can be GUESSED. If you can't understand or track the wiring to KNOW how it's wired then get an electrician to verify the wiring before you go and take any blind advice and possibly burn down your house.


The only way to correctly handle this is to have Google or Alexis ask how to do handle this with the one correct answer being the question, "African or European?"

Yeah. I agree. This 5 switch thing is interesting, scary and puzzling all at once!


I'm certainly not an electrician, but this is truly puzzling. It seems to me there must be some sort of logic controller or relay in the fan unit. I can't think of any way where any on and all off would work electrically.

If this is not an N-Way it's likely a central fan with...and... get this... Insteon controllers. Yes this is a thing and Insteon is used by many HVAC subsystems for N-Way control purposes. So before mucking around with it get an Electrician to verify the wiring. Is this a N-Way standard setup? If not then it's likely Insteon or another wired control system for this fan setup. There's a myriad of options out there outside of the normal home automation realm that most are not familiar with and used a lot with HVAC and commercial control systems.

One thing is for sure. If you don't know. Don't touch/break it!

Name and model of this device? If we had the installation instructions, we could probably give better advice.

if it has a standard 120v plug on the end. you can buy the zooz power plug and then you would know if it was on and could set an alert to tell you if its on to long... that wouldn't automate but let you know its on at least. you could get rid of all the switches and do something with motion sensors in the bathroom in combo with the zooz plug. that might get you where you wanna be.

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This is what I'm thinking. Thank you. But I'll research it more first.

I'm going to research it some more. I put in an inquiry to the builder. What I know for certain:

Fantech FG Series fan, has one 120v line feeding it.
5 switches that are all "plain-jane" type on/off toggles.

What I don't know:
Where do the wires from the 5 switches go? And how do they become one wire to the fan?

I won't do anything until I hear from the building.

African, unladen.