Should I change my smart heating system?

Possibly size of the house is a key component here, lol. My miniature 60sqm probably not a good barometer.
 
Do you not have normal TRVs on your radiators already? Just set them to 3/4, or look up the manual for your TRVs and see what temperature the 1-6 values represent. All smart thermostats do is the same thing but let you control it on your phone, it's a lot of money for that 'convenience'.

Would the cost of replacing your TRVs in all of your rooms really save you that much money?

Example for TRVs:

And the manual:
0 - closed
Frost - 6 C
1 - 8C
2 - 12C
3 - 16C
4 - 20C
5 - 23C
6 - 26C

I suppose the benefit the smart ones give is that you could lower the temperature at certain times and increase them at others all automatically, whereas the old TRVs will be constant unless you get off your bum and change them all. Depends on your use case for certain rooms, that you want them to be warmer at certain times of the day or not.

They still don't seem like a 'save you money' piece of technology, rather a 'quality of life' piece of technology.
That is not at all how what thermostats work.
To say they are the same as normal TRVs asked how little you understand.

Normal TRV controls the temperature when the heating is on by the main thermostat.

Smart TRV is a thermostat and has full control of your boiler.
Mine has paid for itself and continues to save me a lot of money.
 
Possibly size of the house is a key component here, lol. My miniature 60sqm probably not a good barometer.

I guess it's the number of rooms and radiators you have. Our house is quite old and whilst insulated is probably less efficient than your property.

Smart TRVs can actually switch on the heating (as you know). In the winter some rooms are barely used at weekend (my study for example) so no point in using it. When we use the log burner we put a preprogrammed schedule on the Hive system which helps minimise boiler activity. It's a bit of a faff initially but it's definitely had a positive impact in terms of usage but costs is another thing since rates have changed.

In terms of usage comparing 2020 and 2021 we've lowered our usage by over 2kwh. Not significant but it all counts. We're on track to match that this year if not lower still.
 
Last edited:
That is not at all how what thermostats work.
To say they are the same as normal TRVs asked how little you understand.

Normal TRV controls the temperature when the heating is on by the main thermostat.

Smart TRV is a thermostat and has full control of your boiler.
Mine has paid for itself and continues to save me a lot of money.
That is not at all how what thermostats work.
To say they are the same as normal TRVs asked how little you understand.

Normal TRV controls the temperature when the heating is on by the main thermostat.

Smart TRV is a thermostat and has full control of your boiler.
Mine has paid for itself and continues to save me a lot of money.
Are you talking about rad TRVs or thermostats? TRVs control whether a radiator valve is open or closed based on the temperature in proximity to that radiator. Thermostats usually turn the whole heating system on or off at certain periods of the day that you program, and also override the on/off based on set temperatures in proximity to the thermostat. Even if your smart TRV is capable of turning on/off your whole heating system, whether or not that’s efficient depends on how your CH runs were set up in the first place, and/or whether you have smart TRVs everywhere. Altering your CH runs to zones and/or replacing all your TRVs with smart ones is not cheap!

Also what did I say was wrong? I didn’t say they were the ‘same’ at all. They seem to cost around £30 a pop minimum. If you’ve got 10 rads that’s £300, plus if you want a smart thermostat on top, that’s probably another £100.

Will they pay for themselves? Totally depends on your use case. OP wants to only heat his room and make the other rooms cooler while he WFH, which would need smart TRVs in the other rooms. Seems a lot of money, when you can just turn the existing non smart TRVs down. And like I said in my first post, if he wants those rooms to always not be warmed very much, that is the cheapest solution. If he wants the rooms to not be warmed while he WFH, but wants them to be warmed in the evening, then he can either remember to alter the manual TRVs every day or get a smart one that can have different TRV temperature settings depending on time of day. But as I said before that is a lot of money for ‘convenience’ and I highly doubt it’d pay off very quickly. If you’ve got some huge house then it may be worthwhile.
 
In our instance it's helped us save over 2kwh of gas. In terms of gas bill we've more than broken even, not by much I'll admit but from the initial investment it's definitely helping. The advantage of smart trvs is you can set them remotely, have multiple programmes (e.g. away on holiday/weekend, log burner in use, weekend mode (i.e. office not in use)) etc. It makes it really quick and easy to manage your heating rather than manually opening / closing over a dozen TRVs to suit your habit on the day. Heck you can even ask Google/Alexa to set the premade programme (it's what I've done). Lazy? Maybe. Efficient use of time, definitely. Saving money, so far qualitatively, yes.

It's a one off investment and if your home is set up to be "smart" then why not? This is a tech forum after all! We have 7 smart TRVs, and we have 4 normal TRVs, the normal TRVs are in hallway and landing, and the bathrooms. It works for us, but I get it's not for everyone. If you use them properly I think they're a worthwhile investment. They're also not very expensive to be fair.
 
All the going away for holidays/weekends you can solve by just setting your central thermostat down or off completely (or frost protection).

Having a smart thermostat I think can be worthwhile (I have one, although it was an Xmas present), TRVs, I just don’t see it personally. But like I said if you’ve got a very large house, and your CH loops are set up with them in mind (and/or zones) then I can see how they could be effective. But in the vast majority of peoples homes, I doubt they would offer a good ROI, over any sensible period of time.
 
All the going away for holidays/weekends you can solve by just setting your central thermostat down or off completely (or frost protection).

Having a smart thermostat I think can be worthwhile (I have one, although it was an Xmas present), TRVs, I just don’t see it personally. But like I said if you’ve got a very large house, and your CH loops are set up with them in mind (and/or zones) then I can see how they could be effective. But in the vast majority of peoples homes, I doubt they would offer a good ROI, over any sensible period of time.
For instance the wife is at home all day so we have just the living room heating on.
Then at bedtime the downstairs rooms turn off and the bedrooms are set to around 15c.
The babies room is set to 18c.
At weekend we also heat up the dining room as well as the living room.

You can't have that control with standard TRVs. It's saved me a fortune only heating the rooms I need to. It all makes use of opentherm as well for extra high efficient boiler use as during winter for instance the boiler runs almost constantly never cycling on and off.
 
For instance the wife is at home all day so we have just the living room heating on.
Then at bedtime the downstairs rooms turn off and the bedrooms are set to around 15c.
The babies room is set to 18c.
At weekend we also heat up the dining room as well as the living room.

You can't have that control with standard TRVs. It's saved me a fortune only heating the rooms I need to. It all makes use of opentherm as well for extra high efficient boiler use as during winter for instance the boiler runs almost constantly never cycling on and off.
He's got it in his head that it's not for him but that we're wrong. No point in trying to convince him.
 
All the going away for holidays/weekends you can solve by just setting your central thermostat down or off completely (or frost protection).

Having a smart thermostat I think can be worthwhile (I have one, although it was an Xmas present), TRVs, I just don’t see it personally. But like I said if you’ve got a very large house, and your CH loops are set up with them in mind (and/or zones) then I can see how they could be effective. But in the vast majority of peoples homes, I doubt they would offer a good ROI, over any sensible period of time.
The opposite use case is our main one. In winter when the little ones room drops below 17.5 it turns on the heating till it hits 19. No other room heats unless they're below their targets.
 
He's got it in his head that it's not for him but that we're wrong. No point in trying to convince him.
Yeah I'm getting that feeling.
This winter we'll most likely just heat the living room to around 18c through the day and all bedrooms to 12c at night (or what ever the dew point is to avoid any damp)
 
I think your missing my point!

I'm not disagreeing with what you say about the cost of these and how long it will take for them to pay for themselves, and at no point have I disputed that.

Smart TRV's will ultimately use less energy than standard TRV's (unless you adjust them manually on a daily basis).

You saying they are nothing more than for convenience, may well be your opinion. But it's factually incorrect.

Why would you need to adjust standard TRV’s on a daily basis?
Some rooms I keep mine on low setting all the time that I don’t go in often.
 
Last edited:
Some rooms I keep mine on low setting all the time that I don’t go in often.


Which is fine for those you want to keep at a constant temp, day and day out when ever the heating is on to do so.

For all the other rooms a smart trv will allow you to have different temperatures in that room throughout the day/week based on what you want. Peoples coming and going etc..

For example, if you are working from home you can have those rads in your office keeping you comfortable while the others rads in the house are running a cooler temp because the kids are at school. Then when the kids or other people come home those rads will increase each room temp for that requirement, and then back down at bedtime. It would be like having a programmable room stat for each room instead of one stat controlling the whole house, and just having TRV's set at one room temp (unless you adjust them manually all the time). :)
 
For instance the wife is at home all day so we have just the living room heating on.
Then at bedtime the downstairs rooms turn off and the bedrooms are set to around 15c.
The babies room is set to 18c.
At weekend we also heat up the dining room as well as the living room.

You can't have that control with standard TRVs. It's saved me a fortune only heating the rooms I need to. It all makes use of opentherm as well for extra high efficient boiler use as during winter for instance the boiler runs almost constantly never cycling on and off.
The bit where you say 'Saved me a fortune heating the rooms I need to' - thats the bit I'm looking to find answers or someone to explain if by having the boiler turn on will save money in the long run.
What I want to know, turning on the boiler to heat certain rooms will cost less than turning on the boiler to heat up the whole house?

Is it that those radiators are quicker to get warm to bring certain rooms up to temp ?
 
I tried the Hive smart TRVs and gave up, it was useless. I just couldn't get them to work within the temperature required.

Might revisit them in the future, though.
 
The bit where you say 'Saved me a fortune heating the rooms I need to' - thats the bit I'm looking to find answers or someone to explain if by having the boiler turn on will save money in the long run.
What I want to know, turning on the boiler to heat certain rooms will cost less than turning on the boiler to heat up the whole house?

Is it that those radiators are quicker to get warm to bring certain rooms up to temp ?
No. It's about losses. If each room is capable of losing an amount of heat and you only pump heat into one of them the losses are reduced. Simple as that.
I can heat my whole house from 10c to 20c in minutes if I wanted to.
Opentherm will work that out for me the bigger the gap the hotter the boiler runs, when the room is at the set temp it turns the boiler as low as it can to maintain that temperature and keep the boiler on permanently if possible. Within reason as boilers have a modulation some are better than others, for instance my 32kw is actually capable of going lower than some other 28kw boilers.
It's an important spec that people and a lot of installers ignore. They just want to fit it and get the money. It's why I did it myself.
 
Back
Top Bottom