Smart TRV valves - any experiences

Yes - I had 4 rads controlled by Hive wireless TRVs, as part of the Hive main thermoststat/control thing (I think they needed that to work - although I can't be sure). Worked very well - quite reliable. I used the system to turn off the top 2 floors when required.

Downsides I found - app based, so you have to change things on the phone; quite battery heavy (4 AAs IIRC per valve per year); and expensive now - so much so I haven't got them in my new home. I think they were 4 for £100 - double that now.

Have a look at Honeywell/Resideo Evohome. I've had that system installed for about 7 years and it has worked well. The batteries in the rad valves need replacing every 12-15 months but that's all that's been needed. It's great to be able to set individual programs for each room, and to control it from my mobile. I've got the same system controlling the DHW and that's been slightly less reliable because of the signalling protocol between the temperature transmitter and the controller, which doesn't handshake. But it's still great to be able to remotely control DHW heating.

We have the Hive system with programmable TRVs on all radiators except the bathroom. I have been very pleased with the system particularly the ability to request heat on demand what this does is actually switch on the heating system if any of the TRVs detects a fall in room temperature. Without heat on demand any smart TRV is just a simple programmable valve. The hive heat on demand does require you to have the Hive receiver/thermostat for the individual valves to communicate with in order to fire up the boiler. It is possible to heat individual rooms if need be.

We have our system set up on basic time and temperature settings and outside the heating periods if we wish to heat up one room or more we use Alexa voice controls to set either the whole system or individual rooms to the desired temperature.

The only criticism I have is that some valves need to recalibrate on occasions not often but enough to be annoying. This usually results in the heating on the radiator in question coming on after it has sufficiently cooled down and slowly heating up to 25deg C whilst it recalibrates usually overnight. This can be a PITA if it is the bedroom radiators.

I am surprised how well the batteries last in the individual TRVs considering they are on all the time and they activate what from the sound of it are servo motors to open and close the valves.

Richard

I think if you want scheduling I think you need an app. I have Drayton Wiser and I really like it, but it will cost more than £100.

Dave

Before I had the ASHP I installed some Radbot TRVs - these are independent in that they (try to) sense room occupancy (by light levels) and then dial up the temperature based on that rather than any kind of programming. This worked moderately well and likely better than programmable ones - the problem with programming is that it's another job to do and you have to have a predictable routine in order to program things in advance, otherwise you're cold, and if you're cold you need to mess with the app. The Radbots just had a 'press for heat' button on the top where pressing it would give you a half hour boost if you wanted it (two taps for 1h, three taps for

The downside with them was they didn't communicate with the boiler, so they couldn't call for heat if the hall thermostat had decided to turn off the boiler but another room was cold.

I also tried a Tuya-based wifi/zigbee TRV from Aliexpress, which was unreliable trash (kept getting stuck and needing batteries pulling to reset)

Theo

I am resigned to everything being "app" based. However the ones I have in mind are Tuya which I already use. And that feeds into Google home anyway.

Thanks to all for replying. Definitely looks like an avenue worth pursuing.

That sounds cheaper than I would have anticipated.

I live in a modest, reasonably well-insulated semi. I tend to spend much of my days at my computer, which is in the south-facing dining room which is adequately warmed by the sun for much of the year. The lounge does not need heat when it is empty during the day, or is being warmed by the gas fire.

My partner has an office in the third bedroom, but only uses it irregularly.

I have used some add-on Conrad TRV controllers with individual wireless stats, which worked reasonably well, but in several instances the base TRV eventually mechanically failed open. The lack of a call-for-heat signal is another issue.

Long-term there is an argument that I should have some form of intelligent valve, with remote thermostat and the ability to call for heat, but this is quite an expensive solution, and developments are still ongoing.

Since the kit I am aware of generally makes use of the existing valve, just screwing on a control unit, then it seems to me that the most important first step is getting working valves, that would be up to the task, which my existing Bulldog ones demonstrably are not.

I could then continue with a mix of standard TRVs and my existing control units, until I was happy about the cost/ benefit of a "Smart" system.

I know that TRVs are supposedly interchangeable, but I am loath to risk diving in to replace them myself, since any issues making them watertight with original olives, or lining up with existing pipework, could leave me without a working heating system.

I first wrote the above a couple of years ago, and I am astonished how well the system seems to have coped with TRVs stuck open.

Chris

If you are replacing existing TRVs it is highly unlikely you will have to change the valve itself it should just be a case of removing one head and replacing it with a smart TRV. I do not know about other systems but the Hive valves come with a number of adaptors and it should be possible to fit all popular valves. We have a collection of valves from several different manufacturers and all my heads simply fitted without having to use any of the adaptors.

What you cannot do is fit to standard mechanical valve, in that case you will have to buy a bog standard TRV and dispose of the head fit the valve with the smart head. At one time BG did provide a replacement valve but that seems to have stopped, if I remember correctly it was at a price that meant buying a complete TRV at one of the sheds was cheaper.

Richard

Hive have a handy guide of the different types:

(There are also 3D printable adapters available)

Theo

But how does that control the boiler. I assume it runs all the time, and the stat shuts off as the hot water re-cycles.

The thing with wiser is that it only turns the boiler on when one of the rads needs heat.

Dave

I think that if you re-read what I actually wrote, which is trimmed above you will see that your response fails to understand it.

Chris

Couldn't that also have disadvantages? The boiler firing inefficiently (short cycling) to heat just one of the lesser rooms. The boiler firing up where someone has opened a window to air a room.

Sorry I left out the fact I *already* have a smart thermostat. It's in the most useless place imaginable, but can be controlled via google.

That would be setup using a Google Home automation routine: "When thermostat x reads less than y then call for heat".

You can also get 3 indoor smart thermometers for £30 on Amazon. So you can create zones using those too.

I have a Honeywell Evohome system. One advantage of this system is that it can be controlled from the Home Display or an App BUT The program and scheduling info resides in the Display/Controller itself so is NOT dependant on an internet connection or any 3rd party server to run unlike some others.

Drayton Wiser is the same. It only needs the 3rd party server if you want to adjust when you are not on the local network...

Dave

It won't do that. It has hysterysis and predictive operation depending on room history and outdoor tep.

It has draught detection...

Dave

Will it really continually check. If you are using Google Home then aren't you dependant on cloud services or do you already have some sort of hub?

Yes, but then you are having to mess with Google home and custom automation. The great thing about Wiser is it just works out of the box. You just set schedules in the app, they are stored in the controller and away you go....

Dave

No hub. This all started as a get up & running asap. I already had the non-hub thermostat (Tuya compatible) so it made sense to add to that. The same app now controls smart switches too. I have another app (Tapo) which does bulbs and blind motors and plugs.

When Google home was setup, it found all my smart apps and was able to incorporate them.

One mans "mess around" is another mans fix. Because Google Home is connected to Google assistant all of this stuff can be voice controlled, which is a boon for SWMBO whose eyes are f***ed (as well might mine be if the glaucoma isn't controlled). A one word command can set off a whole series of actions.