TRV valves on radiators

BernardM

http://www.askjeff.co.uk/jeffs-handy-tips-central-heating-effeciency/

System

BernardM wrote: »

Anyone read/agree with these articles, I think they are bit of a waste of time and money fitting them in most houses.

Try keeping your whole home warm and dry this winter with this approach. Timer on Constant setting and just main stat down to 18 or 16 celsius at night.

Hence my advice that in cold weather, rather than run your central heating for two hours in the morning and six in the evening, it is better to keep it on the “24 hour” setting, but running at a low boiler temperature. Turn all your thermostatic radiator valves to the highest number, or “max”, and turn the boiler thermostat down to 1, or “min”. The room thermostat can be at whatever temperature you find comfortable – I’d suggest 19C or 20C during the day, and perhaps down to 16C at night, but you can make your own choices. This advice is offered for its guiding principles, not as rigid instructions.

I think that the experts at Salford University have a different view. They have a test house and their results - now quoted frequently by control manufacturers - is as follows:

House with No heating controls - Savings 0% (£5.31/day)

House with just a Room Stat - Savings 12% (£4.68/day)

House with Room Stat and TRVs - Savings 41% (£3.15/day)

FWiW, I replaced a hall stat and manual TRVs with a Honeywell Evohome zoning system about 2.5 years ago. My gas usage has fallen by c.20%. We have heat when and where we want it.

Even the experts who appeared before a recent HoC Committee admitted that if every house in the country was fitted with a Hive thermostat rather than a smart meter, consumers could expect 10 times the savings the smart metering will achieve.

BoxerfanUK

I've noticed a couple of references on this thread to the Honeywell Evohome system, which is something I've been looking into myself recently.

I just wonder, for those that have it, how effective it's been at actually controlling the individual room temperatures? I don't dispute the potential savings (in spite of the high installation cost) but in practice does it maintain good room temperatures?

Reason I ask the above question is currently we have a dual zone system up and downstairs with temp controlled by separate stats in hall and landing. As far as I gather, Evohome does away with these and individually controls the temp to each Rad' linked wirelessly to the Boiler, my point being, each stat being on the TRV means it's very close to the Rad' so if you set the temp to say, 23 degrees, as it's right next to the rad will it shut off more quickly because of this, whilst leaving the rest of the room not up to the required temp?

Ideally I would like a system where you would have a wireless room stat in the middle of EVERY ROOM, away from the Rad' itself.

Hope this makes sense.

SplanK

I have had it installed for a couple of months. ITs required a bit of tweaking to get it right, but it has evened out the temperature throughout the house a treat. Guesswork is taken out of when to have the heating come on with optimum start. You tell it what temperature you want it to be at a certain time, and it will sort it for you. It will work out over a couple of weeks how long it takes to heat a room and turn the heating on accordingly to meet that target, it then works out how long it takes for the room to cool down and provide just the right amount of 'tick over' to maintain it.




I ignore the temperature reading and just go of what is comfortable but they do a great job of reading the rooms real temp despite their close proximity to the rad. However you can get wireless thermostats which red the temp of the room rather than the TRV itself but you are then adding to the cost. My advise would be see how you get on with the TRV first, live with it for a while THEN add later. Even with one my my TRV's behind a sofa, I was surprised how well its able to cope and hold the room temperature!


It's a costly system, and although I guess it will save me on my gas bills (not a huge amount a I already had TRV's in most rooms), I didn't buy it for that, I bought it to make the house more tweakable and a nice place to live in through winter. Not too hot, not too cold.


It does help however if you keep the doors shut

BernardM

Or replace the lot with manual valves and DIY a neglected practice that plumbers and heating engineers used to carry out as a matter of course.
https://www.homebuilding.co.uk/how-to-balance-radiators/

System

BoxerfanUK wrote: »

I've noticed a couple of references on this thread to the Honeywell Evohome system, which is something I've been looking into myself recently.

I just wonder, for those that have it, how effective it's been at actually controlling the individual room temperatures? I don't dispute the potential savings (in spite of the high installation cost) but in practice does it maintain good room temperatures?

Reason I ask the above question is currently we have a dual zone system up and downstairs with temp controlled by separate stats in hall and landing. As far as I gather, Evohome does away with these and individually controls the temp to each Rad' linked wirelessly to the Boiler, my point being, each stat being on the TRV means it's very close to the Rad' so if you set the temp to say, 23 degrees, as it's right next to the rad will it shut off more quickly because of this, whilst leaving the rest of the room not up to the required temp?

Ideally I would like a system where you would have a wireless room stat in the middle of EVERY ROOM, away from the Rad' itself.

Hope this makes sense.

This will be my third Winter with Evohome. The TRVs work extremely well and provided that the TRV is not placed behind furniture, curtains etc then the reading is pretty well spot on for most people. The 'geeks' will tell you that there is a discrepancy as the valves open and close. You can add a thermostat to every zone; however, I doubt whether the extra investment is actually worth it. Each zone can have as many TRVs as you need with one acting as the room sensor. The Evohome controller can also act as a zone sensor (I use it to control the TRVs in my hall, landing and stairs.)

Currently, I am looking at a boiler replacement and I weill probably select either a Viessmann, Atag or Intergas as they are Opentherm compatible with Evohome. Opentherm control provides better condensing boiler modulation than, say, weather compensation as Evohome regulates boiler output to manage demand. It follows that when there is only a small demand for heat the radiators will be warm rather than hot.

Evohome is not cheap, and it is not without its faults, but it is the best domestic heating control system on the market with excellent technical support.

BernardM

Independently tested as not the best on the market with a pretty poor score of 57% by Which? for £219
The cheaper model single zone performed better than it. £106 again poor score of 60%.

http://www.telegraph.co.uk/lifestyle/interiors/jeffhowell/8278429/Home-improvements-What-is-radiator-balancing.html

Biggles

BernardM wrote: »

Independently tested as not the best on the market with a pretty poor score of 57% by Which? for £219

But the only one out of all of them that can control multiple rooms independently, and hot water as well.

http://www.telegraph.co.uk/lifestyle/interiors/jeffhowell/8278429/Home-improvements-What-is-radiator-balancing.html

I'm a bit baffled by the way this article is written. Surely, if you have TRVs on all radiators, you just have to ensure that all the lockshield valves are fully open?

Jonesya

Rather than Evohome at several hundred quid or more, I think a few strategically placed electronic TRVs at £15 each make sense.

Personally I keep most rooms at around a constant temperature when I'm at home so TRVs in combination with the programmer/timer work fine but a few rooms like the bathroom, where you want it hotter at certain times of day, the electronic TRVs make sense.

Set the electronic TRv to crank it up really warm and cosy in the mornings when you're showering etc then drop the temperatures down for the rest of the day.

beefturnmail

I have them in a new-build town house and they are definitely worth it, as the ground floor is much colder than the upper floors - I can get away with not having the rads on at all in the top-floor bedrooms apart from when it's very cold.


One thing is, if you do install them, make sure to not put them on the rads in the same room as your main thermostat, as you can create a conflict - e.g. the TRV is set to 20C and the thermostat to 22C the rad will shut off at 20C and the boiler will keep running and running as the temperature will never rise to 22C.