OK many options, a cheap battery powered thermostat like this,
will work and give you a programmable temperature so it can change through the day.
Only wireless smart version is as
@stem says, the Nest e, any other wireless thermostat will need to be fitted at the boiler. So just fitted Wiser, they use same back plate as Hive, but Wiser has three versions, and Hive only two. Also Wiser has OpenTherm, Hive does not, and not that much more expensive, but the whole idea of the more expensive versions be it Hive, Wiser, ecoHome, Tado etc, is the TRV is King.
These more expensive thermostats with the exception of the silly Nest, are more hubs than thermostats, and each room becomes its own zone.
So big question why zone the zones? In my house I have a garage turned into a flat under the main house, so yes my main house and the flat are now two independent zones, so most of the winter the flat is not heated, there is enough heat from the boiler running not to freeze anything. But main house, 4 bedrooms are not used as bedrooms, one is an office, one a craft room, so I want each room independent;y controlled. So to have zone valves up and down stairs for me would not work, so I have 9 motorised TRV heads, so to some extent the rooms are all independent, I say to some extent as clearly if boiler not running the rooms will not heat up.
Linked TRV heads are around £60 each, and non linked £20 both are programmable, at the moment non of mine are linked, I have just fitted a Wiser thermostat so now I can if I want use a linked TRV head.
However the Wiser thermostat works with two AA batteries, and can be either wall mounted, or put on a table, so could simply move it room to room to ensure boiler fires when required. The TRV heads do the important work.
So the Wiser as an example
the hub to left comes as three versions, the three channel
will work two zones for heating and one for DHW, the two channel will work one zone for heating and one for DHW, so even though you don't need control for DHW likely you would still need the three channel version.
Or combine both zones together, and once you have programmable TRV heads, no real need for zones, so the stumbling block is the price.
£488 takes some getting back in reduced gas bills, the hub would go next to boiler, and the existing zone valves would work together or could be removed, but as said, I have just got a single zone Wiser because areas of my main house were not getting to temperature required before the hall wall mounted thermostats switched off. So not got to save money, got for better comfort, but I have oil not gas, and big difference is oil does not modulate, that is turn down output.
So with gas, why have a wall thermostat? In winter the boiler runs all day, but not flat out, sequence of events should be, boiler starts and all TRV's are open, so all rooms heat, as each room gets close to temperature required the TRV's start to close, as this happens more water is forced though those still open, until the pressure is enough to lift the by-pass valve, then hot water is returned to the boiler, and so the boiler reduced output, so each radiators cools, but they do not switch off, so there is little or no hysteresis in the rooms temperature, it is maintained as set.
But there is one flaw, as summer arrives it will never switch off, it will keep firing up, seeing if the return water is hot or not, and turning off again, so better if we have some thing (wall thermostat for example) to turn boiler off. If linked to the TRV heads then great, but even without careful adjustment of the lock shield valves one can with gas (not oil as oil is digital i.e. on/off gas is better, it is analogue and for central heating analogue is king) get a reasonable result without linking.
Where it all gets complex is when you want to turn off whole house or rooms, so then we look as a sequence, kitchen used first on return home, so we turn that room on first, closely followed by dinning room, closely followed by living room, this can speed up the reheat.
Three of my TRV heads and my Nest Gen 3 thermostat have option for geofencing, so turn on as you arrive home, not found it works too well to be frank, detects my return too late. A google says
You can automate Wiser's Away Mode by allowing smart heating geofencing to save energy while you're out of the house. Once registered, simply link your account to IFTTT in Settings, then visit the Wiser Home integrations channel on the IFTTT site to download the Applets and you're ready to go.
not tried it, did try using IFTTT when it was free with the Energenie TRV heads, not impressed. IFTTT = If this then that.
The Smart technology works well once set up, I use voice commands, with Nest Mini's (Alexa is same idea) but setting it all up to start with is not so easy. Maybe my age at 73 I don't catch on so fast.
