OK little more time, going back around 4 years ago my son sang the praises of Nest, and I was going to fit Nest to mothers house, and at that time Energenie and Nest had a partnership so decided to fit the TRV heads first, then fit Nest, they were an improvement, but what became apparent was lock shield valve was also important specially when TRV on the return, it takes the valve around 3 to 5 minutes to close, a lot faster than wax, but in that time unless the lock shield is adjusted the radiator can get stinking hot, so the room temperature over shoots, so by reducing the lock shield setting if it over shot and opening it a bit if not reaching temperature I found except for room with bay window where the sun caused over shoot, once set, then the room would stay at the setting selected.
However the valves have rather an OTT anti-hysteresis software built in, so when the schedule went from 16°C over night to 20°C in the morning it took 3 hours to reach 20°C so I set to go to 22°C for 1 hour then to 20°C and this worked great, but then it was how to integrate with wall thermostat, I found setting the TRV to 2°C below the wall thermostat setting worked fine, it was in the hall so set to around 19°C and TRV set to 17°C and on a warm day the boiler would turn off, other wise it modulated as it was designed to do, so once the lock shield was set, they worked that well, never bothered getting Nest.
On mothers death and selling the house all wax thermostat heads replaced, it still worked well, not as good as with electronic heads, but it was clear the setting of the lock shield valve was the key, but old wax heads marked *123456 which is about as much good as a chocolate fire guard, what had allowed me to set the lock shield correctly was a head reporting target and current temperatures in °C.
So moved to new house, boiler now oil not gas, so does not modulate, fitted the 4 energenie heads, but 15 radiators, 4 not used, one with no TRV (bathroom) and in shower room very small, so wanted 5 more electronic TRV heads, found an advert for Eqiva bluetooth eQ-3 at £15 each, so £75 for 5, little uncertain but went for it, when they arrived found they also have a window open function, so one in kitchen so when unloading food it switches off for 20 minutes, this is settable, also the buttons and dial allow you to work them without a PC or phone, easier to set schedule with phone, but once set do not use bluetooth, the blue tooth will only work with one phone, unlike the energenie which can be altered with any internet enabled device, and they only show target temperature not current, but seem to work if anything better than the energenie, so easy go to bedroom early press eco/comfort button and moves from 17°C to 21°C (which I can set) with just on press, the energenie also has a button but only works on default settings 16°C and 21°C you can't set it, so you NEED the phone with energenie, but with eQ-3 phone just means you don't need to get up, you can get non bluetooth for less than £10.
This house had no wall thermostat, there clearly had been one as receiver still there, but no actually thermostat, the programmer did not seem to work, and there were 3 FCU's and a plug connected with central heating and I found to turn it on/off involved walking outside down a set of steps in into the old garage under the house which had been converted into a granny flat and plug in the pump, and reverse to turn it off, could switch boiler on/off from programmer, but still needed to plug or unplug pump below house, found one core of the three and earth cable was not working so wanted to control it all with two wires, so got Nest, which sends all signals and powers the thermostat with just two wires.
On trying to connect energenie to Nest found altering on phone both changed together as they should, but a schedule change or turning dial it failed to alter the TRV head, so they are working stand alone just with same schedule set, so the eQ-3 could have done that, also eQ-3 bluetooth when used in the same room can be paired, that option is not found with energenie, not saying not there as they can use IFTTT which can allow all sorts like geofencing for example, but Nest geofencing and occupancy detection turns boiler off, so no real need for TRV to do it as well.
Anyway all rooms within 1°C of settings, and hall TRV set around 3°C cooler than wall thermostat, found by experiment wall thermostat being higher it is always showing about 3 to 4°C hotter than the TRV, but hall with stairs and radiator so far from wall thermostat is odd one out, all other rooms seem spot on.
I will likely get another 5 eQ-3 units for flat and shower room, but not quite yet.
I am told Drayton Wiser TRV heads are smart, and work out when to close so room just hits target, and spec wise do seem the best, also expensive. Two energenie TRV heads cost £50 but also need a hub, I also have energenie light switches, sockets, and energy monitors all use same hub, so not so bad when split with so many devices.
