What are the best smart thermostats for flats? Nest? Hive? Honeywell?

[dodgem]

My electrician has installed a 3 core hardwire for a wired in thermostat to be connected to my combi boiler.

I have a vaillant ecotech boiler, and my plumber said he just needs 2 of the wires to plug into the ebus socket inside the boiler.

I have no idea what thermostats I can use.

I asked my plumber to recommend a smart thermostat but he has no clue about smart thermostats as I've asked him to recommend a thermostat based on the wired the electrician has installed, and he can't!

Can anyone recommend what I should do?

 

[ericmark]

It does depend on the home, with my old open plan house, heat rises, so one thermostat down stairs between the two rooms was good enough. This house has doors, so a single thermostat will not work, I have 16 thermostats, two on the wall, and 14 built into the radiators thermostatic radiator valves (TRV) I don't have an option of using ebus, but all TRV's gradually open and close, and the wall thermostat only turns on/off a few times a day, so in real terms the TRV's do all the work.

So if we look at options, Hive does not have ebus, Nest does not connect to TRV's, Tado one has to be careful, some will connect to TRV's and have ebus, but not all, Honeywell evohome was one of the first, and does connect to TRV heads and has the option of an OpenTherm add on, and the Drayton Wiser also has an add on, which can also work OpenTherm and connect to TRV heads. So that gives three makes.

The comparison is really how good the TRV is, the thermostat is really only a hub, the Wiser TRV claims to work out re-heating times, so set to heat to 20ºC at 8 am and it works out when to turn on to get room at 20ºC at 8 am. As to if it works not a clue.

I have three makes of TRV, Energenie, Kasa, and eQ-3, non connect to my wall thermostat, however the algorithms in each one vary, the Energenie the anti hysteresis software is OTT, set to 20ºC at 7 am and it is nearly 11 am before it gets there, so I set to 22ºC at 7 am and 20ºC at 8 am and then it is at 20ºC at 8 am. However this means any idea of geofencing is not going to work. I did try geofencing with the Energenie which uses IFTTT, but it was not much good, I have also tried it with the wall thermostat, which is Nest Gen 3, this was also a failure, you can't set the distance with Nest only control is Eco and Comfort setting, and there is simply not enough time for it to re-heat from 17ºC to 20ºC in the time it allows.

I have also had it completely fail when the EE mast went down, the real problem was every time I approached the thermostat the built in PIR would detect me and turn up heating, but since not detecting phone, it would then turn back down to Eco setting, so it took some time to work out what was going on, the geofencing was then disabled.

I can with my phone look at 4 out of 9 electronic TRV heads and the Nest Gen 3 thermostat and adjust setting, any where that I have phone signal, the other 5 are bluetooth, so I need to be really in the room to adjust with phone. However it is rare I need to use phone, just spent a few days in the North East went to Bemish, and yes set Nest to away, and one return called into services where I turned heating up again. But this is only time this year, I simply use pre-set times.

I will look at temperature in the summer, shown by the TRV, and decide if the AC needs turning on, but that's because it is a cheap AC and the condensate bottle will over flow if it runs too long unattended. Better idea would be a hole in the wall for the condensate pipe.

I thought being able to control heating from the phone was a really good idea, however now I have the option, I find simple times work a lot better.

The Kasa (TP-Link) is by far the best of the TRV's I have, and it does allow me to look at how it has done over the day, remember my boiler is not a modulating one, runs on oil, so will never work as well as a gas modulating type, but it does seem the comparison has to be how well the TRV works with most homes, the wall thermostat/hub only relays info to the boiler.

Also although you may need some linked TRV heads, likely you don't need all to be linked, when I got my eQ-3 in 2019 they cost me £15 each, gone up since brexit, but a Wiser TRV costs £37, not much, but when one has 14 radiators it mounts up, EvoHome £70, the non linked Kasa £35, Tado £48, OK still need to wall thermostat as well, but it does seem Drayton Wiser is likely the cheapest option.

 

[stem]

The boiler ebus connection is provided by Valliant to work specifically with other Vaillant products. It doesn't work with Nest, Hive, Honeywell et-al that don't have an e-bus interface

Your boiler can be wired to work with other controls, but not connected via ebus. If this is a new boiler install it is the responsibility of the installer. Get them back to sort it.

​

 

[ericmark]

Thank you @stem so basic same as my oil boiler if not using Valliant's own controls?

I had the same with mothers house and a Worcester Bosch only control into boiler was simple on/off, so I used programmable TRV's to control each room and a wall thermostat to turn off boiler on warm days, it did work, but took some setting up to start with.

I asked my plumber to recommend a smart thermostat but he has no clue about smart thermostats as I've asked him to recommend a thermostat based on the wired the electrician has installed, and he can't!

I had the same, the heating engineer did not have a clue how to wire the boiler, he could service the boiler, measure the flue gases etc, and set pressures and change jets, but not a clue about the electrics. However not as yet seen a modulating oil boiler, so likely didn't need to!

However today we call the guy who fits the boiler a heating and ventilation engineer, to my mind engineer means over level 3 trained, most electricians stop at level 3, as to a plumber, not sure what they do today? Maybe tune organs? As there is very little where we can still use lead, and a plumber is a worker of lead. His job was roofs and pipes, both no longer use lead, some exceptions, seems if lead is not used with organ pipes it changes how they sound, so they still use lead.

Pipe fitters I have worked with, but 36" pipes are not in the same class as 15mm, their skill is rather high, using very clever measurements so when the pipe is craned into position it fits first time. I used to set up the heat treatment as an electrician, and one could hardly call some one working with copper a pipe fitted, maybe called Cupricers? Based on the Latin for copper rather than lead?

However neither the old plumber or the electrician are really trained to fit central heating, it is a specialist job. Personally I would use linked TRV heads, and the thermostat simply turns off the boiler when all TRV's are satisfied. However

My electrician has installed a 3 core hardwire for a wired in thermostat to be connected to my combi boiler.

That is not really going to work unless the boiler uses a 230 volt control system, OpenTherm is 0 - 40 volt, many use 24 volt, and the supply should be taken from the boiler, even with a 230 volt supply, seems neither knew what they were doing, you clearly need some one who does, and that is not me, or either of them.

 

[Mister Banks]

To use Vaillants ebus you will need controls form the page below.........

Thermostats & heating controls | Vaillant

Manage your heating system at the touch of a button ✔ Enjoy comfort ✔ With heating controls from Vaillant → Get started!

www.vaillant.co.uk

They aren't cheap but if you buy a Vaillant boiler you need Vaillant controls. Alternatively you could use simple on/off controls which are cheaper and more readily available but if you do that then you may as well have bought a cheap basic boiler.

 

[ericmark]

Seems good except for one point ambiSENSE says discontinued, so it seems can't use Vaillant controls? I had the same problem with Worcester Bosch lovely modulating boiler, but no controls I could find were designed to work with it. Ended up with the Energenie TRV heads I am still using today.

I got the Energenie as told would work with Nest, but they don't, the Nest thermostat is rather useless.

The problem is as a user we only do it once, and there seems to be nothing to compare different makes. And it seems the installers fit and run, what was installed in my parents house was not fit for purpose, I have looked at what is fitted in this house with the idea to improve, I got a heating engineer to advise, who was at least honest and said he did not have a clue of how to wire up.

It was a mess when I bought the house, so clearly the installer who fitted it to start with needs avoiding with a barge pole.

I look at it and think is it worth modifying? I am fitting new doors and windows, so will re-assess once they are fitted. I know the problem, the hall cools too slowly, and I know a second thermostat with at least one linked TRV will likely solve the problem, but also seems to be some thing hidden behind the plaster board etc, fitted when garage turned into a flat. So I need some one with a heat sensing camera to try and find hidden components. One would expect heating engineers to have these cameras, but ringing around, seems not, it beats me how they can do their job without the tools of the trade?

 

[Mister Banks]

Seems good except for one point ambiSENSE says discontinued, so it seems can't use Vaillant controls? I had the same problem with Worcester Bosch lovely modulating boiler, but no controls I could find were designed to work with it. Ended up with the Energenie TRV heads I am still using today.

I got the Energenie as told would work with Nest, but they don't, the Nest thermostat is rather useless.

The problem is as a user we only do it once, and there seems to be nothing to compare different makes. And it seems the installers fit and run, what was installed in my parents house was not fit for purpose, I have looked at what is fitted in this house with the idea to improve, I got a heating engineer to advise, who was at least honest and said he did not have a clue of how to wire up.

It was a mess when I bought the house, so clearly the installer who fitted it to start with needs avoiding with a barge pole.

I look at it and think is it worth modifying? I am fitting new doors and windows, so will re-assess once they are fitted. I know the problem, the hall cools too slowly, and I know a second thermostat with at least one linked TRV will likely solve the problem, but also seems to be some thing hidden behind the plaster board etc, fitted when garage turned into a flat. So I need some one with a heat sensing camera to try and find hidden components. One would expect heating engineers to have these cameras, but ringing around, seems not, it beats me how they can do their job without the tools of the trade?

Smart TRV’s don’t work very well IME, I have Drayton Wiser, but a lot of people swear by them.

WB boilers have EMS so you need either WB controls such as Easycontrol or but a Nefit Opentherm to EMS converter and buy an Opentherm control. There are mixed results concerning the Nefit converter so you will need to do a bit of research to find a compatible control.

 

[ericmark]

There is a huge difference to working, and working in an efficient manor, now I no longer have a modulating boiler, so it does not matter, but in mothers house I tried to work out what the boiler was doing, and there was nothing the DIY man can do to see how much it is modulating by, or how much latent heat it is gaining from the flue gases, and since when moving to oil my bills went down, with a much larger house, I think it is fair to assume it did not gain much latent heat.

However I can also say the hysteresis with gas was much lower than with oil, the radiators would get hot to start with using gas, but would not turn off, but turn down, which is what one would expect as the TRV's slowly close and the boiler modulates, so we got an even temperature through the day, and the report from the TRV showed it was maintaining the set temperature to within 0.5ºC, so it did seem to work.

As to "Smart" first we must define "Smart", telemetry has been around for many years, the ability to pick up your phone and set the temperature I would not define as "Smart". However to be able to work out how far from home your phone is, and adjust the temperature of the selected rooms so they have reached the set temperature as you walk through the door is "Smart", however Nest Gen 3 falls we short of that, it has two temperature settings which the user can set, and it moves from Eco to Comfort as it detects you have arrived home, but the lack of being able to set how many miles from home before it flits between the two settings, means it falls very short of being "Smart".

I have tried the IFTTT (if this then that) with the Energenie TRV heads, and got no real success, in fact even simple time setting, I had to set to 22ºC at 7 am and then 20ºC at 8 am to get around the OTT anti hysteresis software.

The much cheaper eQ-3 TRV heads did seem to work with the window open detection however, when I open the front door to unload the car, they do seem to turn off for the set ½ hour then turn back on so not heating the street while unloading car, so suppose that does qualify as "Smart", as to the Kasa TRV head, not really tried to use any of the "Smart" features, so can't really comment.

But I also fail to see what a wall thermostat can really do which can be considered "Smart" other than geofencing, most the control is done by the TRV's, and the wall thermostat is little more than a hub, collecting info from the TRV's and relaying the info to the boiler.

In a simple non "Smart" function it is simply if any TRV is not satisfied boiler should run, otherwise boiler should turn off. This is what the Hive does, although the 22ºC limit does mean it can't be used in a room kept warm. But for a hub, can't really call it a thermostat, to assess what the total demand is and instruct the boiler how much heat to produce is rather complex, as a PLC programmer I can see the aims, but not sure if one could really incorporate that into a generic hub seems an impossible task. One would need to instruct the hub as to how many TRV's and how much flow each required and so adjust not only the boiler output but the pump speed and the commissioning engineer would need to set the delays to each TRV so the geofencing would select which rooms to heat first. As far as I am aware there is no way to set this up with domestic software?

So the best option seems to be fixed time, using fixed time one can set it so kitchen, then dinning room, then living room, then hall/landing, then the children's bedrooms and finally the adult bedrooms are heated in sequence allowing as long as radiators are large enough a very fast recovery time as the family returns each day. It would really need fan assisted radiators to have them large enough to get the fast recovery time, and the way plumbed would also alter, as far as I am aware the iVector from Myson can be incorporated into the building management system and can do this sort of thing, very much assisted with the 5 speed fan, but this is well beyond what we are looking for with domestic climate control, the buildings using these systems can often cool as well as heat using the same fan assisted radiators, which also need condensate pumps to safely remove condensate when on cooling cycle.

So back to start, what is "Smart" heating and ventilation control, I would say we are looking more into building management way beyond what is expected for a domestic install. I remember many years ago an installation in "Next" in Chester where the whole of the heating and cooling was controlled by the main office, the Chester staff had no say in how hot or cool the building was, all heating was from the lights, cooling was 7 massive air conditioning units on the roof. I well remember having to install the 150 mm² cable to take the power to the roof, that must have been back in around the 1990's, it was not called "Smart" then it was called telemetry.

So what is "Smart" heating?

 

[veedee]

I'm a Nest guy. Love them.

Just wish they'd switch off the heat quicker when nobodies home.

 

[ericmark]

Old house, open plan, Nest would have worked fine. This house however has doors, so Nest is useless. All depends on the house.