Internet control is not a Smart stat.
Smart is when it uses various inputs to modulate the boiler so it saves energy and tailors burn time to suit your specific property for optimum comfort.
I would agree we expect more from a smart thermostat, but some of the things a smart thermostat does, has one scratching ones head and thinking why. The Nest Gen three was supposed to monitor what changes you made, and work out a sequence to emulate what you had manually done.
I think the main problem with the learning feature, is it did not allow for doors to be left open. So had to turn the feature off, the same applied for many of the features, had to turn off anti-legionnaires, and geo-fencing.
Much is down to design of the house, the on/off thermostat can do a reasonable job, if it's not turned off too often.
My house, 14 heated areas, 15 radiators as two in main living room, since my boiler does not modulate it is slight different, but basic idea is the TRV's control the temperature of each room. But unless linked, they can't turn boiler on/off. So often a wall thermostat it placed in the slowest room to heat up, so all rooms are warm before it switched off.
However, there is a problem, it should not be in a room with alternative heating (including sun through windows), or a room with outside doors, and should be on the ground floor. So an alternative method is to have a few thermostats able to turn on the boiler. I have 3, one in the hall on the wall, traditional location, one in the living room on the wall, and one in wife's bedroom as part of the TRV, the other rooms all have programmable TRV heads, but not linked, only wife's bedroom is linked.
I suppose you could have linked TRV heads in every room, but not found I needed the other linked. There is also no reason why one needs any wall thermostats, could be all done with linked TRV heads. But measure temperature around a room, and one can get 18ºC in one spot and 30ºC in another, due to sun in a bay window, but other factors can cause local warm spots within a room. So measuring at 1200mm to 1400mm high from the floor may be better, it could be worse however, all down to thermals within the room.
So in general the TRV stops a room over heating, and the wall thermostat from under heating. There are claims that my TRV heads (wiser) work out how long it takes to heat the room so will if set at 20ºC at 6pm turn on central heating at 5:35pm as it knows it takes 25 minutes to heat the room, must admit that's smart, but not tested as yet.
Not sure if internet is required, intranet, however that's the bit inside your house, so when I say hey google turn living room to 20ºC it can do so. Not tried IFTTT for geo-fencing, it may be better to Nest version, but with Nest it turned the heat up far too late, better off with simple timed. Nest also does not connect to any TRV heads, so a bit useless anyway.
