Using SmartThings and relay to control my central heating

I’ve recently bought a SmartThings hub, and bought a few Fibaro relays (these seem good… if a bit expensive).

I was thinking the other day that it would be nice to hook up the switch on my central heating thermostat override to the relay, so that I can turn on my heating through SmartThings.

Then it got me thinking, as I was working my way through all of the devices, that they could ALL be replaced.

At the moment, I have a Cosy system fitted by my FirstUtility energy supplier. This consist of…

  1. Electronic Timer
  2. Wall switch (this allows me to switch the heating on/off by pressing the switch)
  3. Cosy Hub (plugged into my router and power supply)
  4. Cosy Thermostat (RF device (I think) that communicates with the Cosy Hub)
  5. A Cosy app on my phone which allows me to control the schedule and switch heating on/off

The simple end result of this, is that based on either temperature/switch/time of day the CH is either on or off.

Now, if I rip out everything, and just put a Fibaro relay over the contacts of the boiler that switch it on and off, could I not just use SmartThings (and my voice via Google Home) to control every element of my heating without the complexities of the above? i.e. I don’t need a thermostat if I have an ST sensor with a temperature reading.

Whatever you do I would design in some kind of backup so you’re not completely reliant on smartthings being operational for the heating to be working.

It’s annoying when it goes down, but be worse if it was cold too!

Plan for hub being offline, your wifi going down, you tweaking a smartapp and accidentally breaking some integration etc.

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if you are not married then go nuts.

Meiriion has good advice for you. You should read old posts about reliability. Are you fault tolerant?