I’m Dutch and don’t speak about these topics often in English so I’m sorry in advance.
I live in a apartment and we get ‘stadswarmte’ this is heating that comes from businsses and datacenters. We don’t have gas.
In our apartment we have floorheating and the water is circulating using a pump. This pump runs 24/7, also when the thermostat doesn’t ask to heat the house.
What I want to achieve is to turn off the floorheating pump when there apartment doesn’t have to be heated. This can save me a lot of energy in a year, especially with my energy prices these days.
I have a power measuring switch I can use with Homey to turn the pump off. The only problem is, when does Homey know the heating has been turned on and the floor heating pump has to be turned on by the smart switch?
I don’t have access to the cattle, so I can’t put another power measuring switch there and see when the power increases and then turn on the floor heating.
Now I’m looking for an external thermometer to put on the pipe the hot water comes into the system. When the temperature hits a threshold the floor heating turns on. If the pipe turns cold, the floor heating turns of.
I have seen multiple solutions from Sonoff and another brand, but they aren’t really ease to setup. I’m looking for an easy Zigbee device with an external temperature sensor to put on the water pipe.
Or does anyone see another good solution to this? Maybe a new thermostat that works with the heating system in my apartment?
I also have floor heating and I replaced the round on/off thermostat from Honeywell with a Tado. On this forum (also the dutch part) are different topics about Tado. The pump of my floor heating is only using 5 watt, so I don’t turn the pomp off.
You could also look at Plugwise (dutch brand) which is working with Homey.
The honeywell round thermostat is just an on/off thermostaat which is controls the valve. It has nothing to do with the hot shower/drink water. If you take it from the wall it has 2 wires which hou can put on a different (smart) on/off thermostat. Tado and plugwise has both the simple on/off function.
You only have floor heating? And in all other rooms you have also thermostatic heating ore also floor heating? And they do work if the heating in the living room is off? Otherwise you also need smart cranes from tado/plugwise on there.
Don’t forget that the pump has to run for a couple of minutes every 24 hours! Otherwise it could get stuck.
If you decide to go for the smart solution.
Dont forget to implement a short power-on every day, even if the watertemperature is low.
When the pump is standing still all summer it might get stuck.
(My non-homey proposal has this function build in)
thats also an option. And a cheaper one. But with a smart thermostat you can also win some whit more sustainable use of energy. 
