The Efficient Home Forum

I'm strongly leaning towards EvoHome as the most flexible system for our large (13 rooms, 3 floors) house with only two people who typically are using only a couple of rooms at any time... I want to be able to set most rooms as 'off' for fuel saving rather than heat even the subset of rooms we are likely to use all together (bedroom, living room, kitchen, 2x bathroom). I don't know of any other system that offers such good per-room control rather than a central thermostat (happy to hear of others though this forum might be a little biased!)

But the TRVs are pretty bulky and ugly in my opinion. I can see why this would be but for my Victorian house, I fear they'll detract from the decor.

Are there other alternatives? Such as having a bypass valve for the radiator(s) in a room which is connected wirelessly to the main controller, and a per-room thermostat?

I would use and inline radiator valve to the radiator (V120-15S) and a HR92 on it if the looks are the issue...

I don't understand. Are you telling me there isn't an alternative...a room thermostat connected to a hidden actuator or something?

You need to have an HR92 to control the flow of water through the radiator. The HR92 is a wirelessly controlled, battery operated motorised valve, The previous reply is suggesting that instead of mounting the HR92 right at the inlet of the rad, you mount it on the supply pipe to the radiator, in a discrete location - eg in a nearby cupboard, or behind curtains or furniture. As the reply suggests, you would use https://theevohomeshop.co.uk/radiator-v ... aight.html to fit the HR92 on the pipe. But if you install it in a place where the ambient temperature is likely to be different to the room, you would need to use a separate temperature sensor (eg DT92E) positioned in the room, rather than the sensor built into the HR92. Then, when setting up the system for that particular zone you would configure the HR92 as the actuator, and the DT92E as the sensor. Don't get too carried away hiding the valves - you need access to replace the 2xAA cells - I replace mine on the same day as my annual boiler service. You'll also need easy access to the valves if you choose to enable manual over-ride of the zone temperatures programmed into the controller. I have disabled over-ride on all my valves. Guests often say "I hope you don't mind, but I turned the radiator up/down a little." I ask whether the temperature is now OK and they always agree that "it's fine now".

Although I have all my valves directly coupled to their radiators, I use DT92E temperature sensors in 3 of my zones: The stairwell, which has multiple rads, and some are in draughty locations near external doors - not a good place for temperature sensor; the kitchen which also has the rad valve next to a door into a cold laundry room, and a bedroom occupied by a young person who uses the floor as a wardrobe - so the valve is often under a foot of very effective insulation! Furthermore, I use the temperature sensor in the EvoHome control unit in the zone where the control unit is situated.

You can place a standard 2-port zone value controlled by a BDR91 on the pipe hidden away somewhere, with a T87RF wireless thermostat in the room. I'm planning on doing similar in my bedroom to avoid the noise of the HR92 radiator controller waking me up in the middle of the night! I'll be running two rads so this would offset the cost of two HR92s.

But the earlier suggestion of using an in line value and the HR92 would be cheaper than a zone valve and BDS91 - I hadn't thought of that!

BenC wrote:But the earlier suggestion of using an in line value and the HR92 would be cheaper than a zone valve and BDS91 - I hadn't thought of that!

Its the best suggestion as doesn't require mains voltage and the HR92's are fully modulating (who wants a 2 port valve swinging around lol)...

Thanks, this is the sort of idea I was after.

Why the T87RF not the cheaper DT92E?

I assume your thought was two actuators wired into one relay box? Interestingly I found you can buy both motorised valves, and mains power rad actuators (£30 each). Can't recall the part number right now.

One limitation, these would ask just be on/off solutions, unlike the HR92? The relay just is on or off?

The EVOHOME Shop wrote:

BenC wrote:But the earlier suggestion of using an in line value and the HR92 would be cheaper than a zone valve and BDS91 - I hadn't thought of that!

Its the best suggestion as doesn't require mains voltage and the HR92's are fully modulating (who wants a 2 port valve swinging around lol)...

and there's the flip side... But then it's mains bad? What is the annual cost per radiator of AA batteries?

MisterBoy wrote:Thanks, this is the sort of idea I was after.

Why the T87RF not the cheaper DT92E?

I assume your thought was two actuators wired into one relay box? Interestingly I found you can buy both motorised valves, and mains power rad actuators (£30 each). Can't recall the part number right now.

One limitation, these would ask just be on/off solutions, unlike the HR92? The relay just is on or off?

BDR91 is TPI controlled but the valve or wired actuator (not advised) would be open or closed, where the HR92's can be anywhere between 0-100%.

You can use a DTS92E but most people don't like the dated look (I personally don't care about the looks).

MisterBoy wrote:and there's the flip side... But then it's mains bad? What is the annual cost per radiator of AA batteries?

The batteries last at least 18 months and when you can buy 40 for £8.95 (https://www.batterystation.co.uk/aa-bat ... 1MQAvD_BwE) will certainly out perform the cost of getting mains voltage to places there isn't any...