Re TRVs - I did read that Nest is compatible with the Energenie just the other day
I have Energenie TRV heads, if I link the TRV to Nest when I change the temperature of Nest with the app it also changes the TRV, but it does not change TRV when it is a programmed change, or when using the dial, so in real terms rather useless.
Also really you want the TRV to tell Nest what to do, not Nest tell the TRV what to do, so rather useless.
So I just program schedules on both Nest and Energenie to compliment each other, but could do that with eQ-3 heads at a fraction of the price.
It is down to location, the area with wall thermostat needs to cool faster than other areas, so it will be calling for heat when other areas need heating, you can trim the lock shield valve and TRV to set heating so the area with wall thermostat is last to reach target temperature, but that is only good when heating up to start with, once at temperature it is the cooling which is important, the area with wall thermostat needs to be the fastest area to cool.
So living room has open fire, so wall thermostat can't go there, plus outside doors which are used, kitchen the same outside door and alternative heating, and the dining room is seldom used, plus outside door, so what it needs is multi-thermostats.
The simple way is a demand for heat system, where the TRV head tells the wall thermostat to turn on even if the room it is fitted in is warm enough, this is what Hive, Evohome, Wiser etc do, odd one out was Nest, which worked the wrong way around, but when google took over nest the withdrew support for working with Energenie, I thought Nest would bring out their own TRV heads, as Hive did, but as yet nothing.
I bought Nest Gen 3 as one I had four Energenie MiHome TRV heads and I thought they would work with Nest, and there was a break in one wire of the triple and earth cable going from main house to where boiler is in the flat (was the garage) so wanted to be able to control DHW and CH with two wires, and the Nest Gen 3 could do that, so the wall thermostat is powered from those two wires, and also controls both DHW and CH with those two wires. Most the others would have relied on wireless only, so seemed a good idea, but the fact the TRV heads will not bring on the boiler has rather spoilt it.
However not really worth ripping out Nest and fitting Hive, Nest still works, even if not very good, and we want double glazing to be replaced, so feel we will put up with Nest for now, and then see how well it works once double glazing is replaced.
