And what do you mean by “smart”
You beat me to it. I fitted smart thermostats to mothers house
they connect to a hub which in turn connects to router and internet, it allows the temperature to be set to change at set times, but the much simpler thermostat
also allows that, and the cheaper one also has a door open detect so it turns off the heating while I unload shopping, but it does not have the IFTTT (If this then that) options which the first has so can't be set to geofence.
Although the first thermostat can geofence the anti-hysteresis software is OTT, so to get the room to 20°C when turning on at 7 am by 8 am had to cheat and set to 22°C at 7 and 20°C at 8.
The Drayton Wiser thermostat (TRV) is claimed to have algorithms which work out how long it take to heat the room, so can adjust the time when it opens to suit. It can also connect to a wall thermostat or hub to tell it when any room needs heat, and the wall unit can connect to an OpenTherm boiler using OpenTherm.
You only show wall thermostat, in the main the wall thermostat is designed to stop a modern boiler cycling as warm weather arrives, they are put in a room normally kept cool (so they can detect warm weather earlier) on ground floor (as heat raises) where there is no alternative heating including sun through windows, and no outside doors. Don't know your house, but in my house no such room.
So we have to compromise, for example in the hall, but since hall does have outside door, we need to also have a TRV to allow fast recovery when door opened but not getting too hot so it closes down system, the relationship between the wall thermostat and the TRV can be simply using same program of temperature setting, but far easier to set up if they are wifi linked.
So a wall thermostat like this
Evohome example allows you to set what the rooms do from either the wall thermostat or likely a computer or smart phone, but some systems only allow you to set with the computer or smart phone, this one
is an example, this looks good on the PC
but you can't set up without a PC or smart phone, where as this one
can use bluetooth but also can be set manually, plus I only paid £15 for them each, and they require no wiring you simply unscrew the original and replace with the eQ-3, the terrier i30
is the same idea.
I actually fitted a Nest Gen 3 to my house, mainly as only two wires to boiler, and with two wires it could charge it and send information for domestic hot water and central heating with just two wires,
it was claimed it worked with the TRV's I already had (Energenie) that was incorrect, it does not connect to any TRV and although may be great with hot air central heating or open plan house, it is not really much good with British system.
As to geofencing yes it had it, but when we had the high winds earlier this year it took out the EE mast local to my house so it thought I was not home and turned off the central heating unless I walked past the thermostat, when the built in PIR detected me and switched heating back on, took me a while to work out what was going on, so now geofencing is disabled.
I have used the
remote in the summer, to tell me room temperature and decide if to turn on the socket connected to the AC unit to cool house before my return, and it seems one could use IFTTT to do this automatic, although never tried it, since we only get 2 or 3 weeks where we used the AC it seems pointless.
Some Ideal boilers are OpenTherm enabled, but combi means the DWH and CH is done by one boiler, it does not mean the boiler can capture the latent heat from flue gas and modulate, it just means one boiler does two jobs.
If you can use OpenTherm it will need some rewiring. And some so called Smart thermostats can't be used with OpenTherm, so as
@Taylortwocities says what do you consider smart is, and what do you want smart to do? I could simply plug my boiler into a smart socket adaptor and switch it on/off remotely, no need for smart thermostat for that, as to geofencing I found when using it there was no option to set distance, only setting I had was eco temperature and comfort temperature, so I could not set it to come one when say 30 miles from home, and it takes my heating over half and hour to heat home from off, so in real terms it was useless, and I simply would forget to set using phone, so simple time was far better.
So what do you want "Smart" heating to do? In spite of the adverts smart meters for example are rather basic, clapping your hands once fitted will not turn the lights on and off. The word smart seems to be used when really the units are not really smart, it just means in some way they connect to internet, so what do you want smart to do.
