the nest thermostat is not battery powered and the receiver is sam as the hive receiver, the nest needs a supply via the USB cable connected to a plug same as a mobile phone, or a designated supply from the receiver, all depends what you want from it
There are three Nest thermostats, well four really but gen 1 not released in the UK, I don't know what gen 2 will do, I have gen 3, which can be hard wired, and a 12 volt DC cable connects the thermostat to the heat link and all power and signals go down same pair of wires, the heat link is 230 volt powered, well I think 100 - 240 volt, but UK it is 230 volt powered, Nest can also use wireless and a 5 volt power to the thermostat, it does not at the moment have it's own TRV heads, it should work with Energenie MiHome although I have had problems, it is volt free, both sets of contacts CH and DHW are independent and you can select power into com or into N/O or N/C contacts, so very versatile, it also supports OpenTherm and connection direct into the boilers ebus. Connection to the router is wireless. There is also Nest e, with this both thermostat and receiver are battery powered, the connection is always wireless between the two and it also has OpenTherm, it is as far as I know the only one where both sender and receiver are battery powered.
Hive there are also at least three versions, there is single channel and duel channel, it can only switch mains voltage, it does not have opentherm, early versions did not have the "heat on demand" but later version do, which means they will work with Hive TRV's the theory is if any TRV demands heat even if the thermostat is satisfied it will still fire the boiler. As with Nest I have heard there are problems getting it to work with the TRV's.
My Nest does show a selection of items as you walk past, what is shows is up to you, when you increase the temperature it shows how long it will take to get there, and with timed changes it works out when the boiler needs to fire up, to be at the target on time. The Energenie TRV heads and the Nest can both use geofencing.
However how well any system works depends on the home and how well fitted, likely EvoHome is the best, Tado will not release info so hard to say, even EvoHome to work with OpenTherm needs an extra module. But as far as I am aware Hive, EvoHome and Tado the TRV head tells the room thermostat what heat is required, Nest is the reverse, the thermostat tells the TRV head what setting it should be, and in my case it works OK using phone to change temperature, but other methods seem a little hit and miss, in that the TRV head has failed to follow.
I think Hive is rather expensive, it depends on how many rooms, but 6 TRV heads with EvoHome is cheaper than 6 TRV heads with Hive, and EvoHome allows you to alter settings at thermostat, Hive you either need to use phone or bend down to the TRV head.
The advantage with Hive and Nest is you can add a bit at a time, start with TRV heads then add wall thermostat, or start with wall thermostat then add TRV heads, EvoHome you have to get all at same time, as room temperature sensed by the TVR head, which is likely the best method anyway, Nest there is no way to set the Energenie MiHome heads without using a hub and PC, Phone or tablet, you can set the wall thermostat, but not the TRV heads.
Thanks for clarifying for me Ian. Install is £79 at the moment.
Neil
I think you will find that is only a part install, and that the TRV heads are extra, the TRV heads
Screwfix price are £54 each, same with Nest the Energenie heads £73 a pair so £36.50 each, (plus hub at £53), Evohome again around £60 each for the heads.
As to if you need all heads same make as thermostat, well I have 4 Energenie and 5 eQ-3 the latter bluetooth at £15 each and work well, there is also Terrier i30 electronic heads stand alone, and price does vary depending on where you buy, found non bluetooth eQ-3 at £10 and Energenie at £100 for 4, the eQ-3 non bluetooth from
Screwfix £22 so can be well worth shopping around.
It took me around 3 hours to install Nest, even longer if I include working out how to wire it, to be fair reason for Nest is Hive and all the others would have required lifting floor boards to install more cables, it was the way Nest could be configured to work with nearly any system which was why selected.
But to install Hive for £79 is a good deal, it would normally cost that just for the hard ware, never mind the installing, Nest e is normally around £150 (Currys) and Hive (Currys) £95 so Hive is around £55 cheaper for the wall thermostat, however what the fitting charges are I don't know. Personally I fitted the TRV heads first, and in the last house they worked well enough without fitting a wall thermostat to match, this house I brought the TRV heads with me from last house, but there was no wall thermostat, to switch on central heating I had to go outside wall down a flight of steps, go into granny flat under house and plug in the central heating pump, there were two wires main house to flat and I needed to control both heating and DHW with just two wires, and Nest would do that, so I bought Nest, had I had option (able to run more wires) and not already had Energenie I would have fitted EvoHome or Hive.
