The eTRV (electronic thermostatic radiator valve) and saving energy in my home

I've just bought an eTRV from Chalmor for £59.99. There are much cheaper electronic TRVs but the reviews on screwfix slated them for noise, low battery life, losing settings when battery fails and other faults.

A side note on pricing on web sites

As side note. When looking around for places to purchase the eTRV I first started on the eTRV web site and the "where to buy" page. I tried to compare prices on various web sites and here the annoyance starts. Some sites show the price excluding VAT, some including VAT, some don't say whether VAT is included or not until you order, some don't show a price for delivery. Some web sites even require you to register and go through the buying process before you can actually find the final price! Why is it so hard to provide this information up front.

Other things I've tried to do to insulate my house

Like many people in the UK I'm finding the fuel price hikes and fuel tax hard to swallow. Last year I emptied my loft and laid down loads of insulation (I definitely had less than the recommended thickness and with a lot of the loft boarded out the insulation was poor). I've tried to get cavity wall insulation but my house is random stone and most companies won't do it. Recently Leeds City Council wrote to us saying a local company might be able to do the cavity wall insulation using poly beads for a small fee. Alas, when the surveyor came and drilled a hole in my wall he said it was not suitable.

Current central heating situation

I have a Worcester Bosch condensing combi boiler which has performed well in the last 6 years until last year (when the expansion vessel broke and the first people we got in to fix it failed to do so).

My central heating system does not have zones although I have TRVs on all but 2 radiators (one because you have to leave one off and the other because I forgot to ask the guy who installed my ensuite last year I wanted the TRV replacing). We have quite a few rooms in the house we don't use that much (3 bedrooms) and the TRVs are turned right down. However, in our main bedroom the TRV is set to a slightly lower than confortable temperature but of course when the heating comes on in the evening the room is heated up even though we are not using it until we go to bed. Up steps the eTRV.


With the eTRV I can program it to only open the valve in our bedroom 30 minutes or so before I go to bed hopefully saving some energy (and eventually recouping the outlay on the eTRV).

The eTRV came with 2 AA batteries, a remote with a watch battery, some collars and the instruction book. I had another radiator with a normal TRV I suspected was not working properly so I decided to set it up on this first (thus verifying the existing TRV was broken). Choosing the correct base ring was easy as only one fitted. The first thing that the manual is not clear about (as far as I'm concerned) is whether you need to use one of the 2 spacers and which one to use. The manual says "In most cases (where the valve pin is taller than 14mm), you will need to fit a spacer inside the base ring" and It is important that you use the correct size space then there is a picture of the 3.5mm spacer in the 28mm base ring and the 2mm spacer in the 30mm base ring but nothing saying if they are interchangeable or how to decide which spacer to use. I chose the 2mm spacer but only based on a) that was shown in the picture and b) with the 2mm spacer the eTRV sat on the base without any gap around the base.

Base ring chosen, spacer fitted and the 3 locating pins pushed in, I then fitted the 2 batteries and attached the eTRV. You then press the grey button on the eTRV and the motor runs for a short while closing the valve. Press the grey button again and it is operational as a normal TRV with the temperature set to 19 degrees C. So far so good.

Now from the hand controller you can do a bewildring amount of stuff.

First I asked it what the room temperature was. It flashes a red LED repeatedly, you count how many flashes and then look that up on a chart where it tells you the temperature (a good point is that the temperatures are marked on the hand controller next to each number key so key 5, 5 flashes represents 20 degrees C). It flashed 9 times suggesting the room temperature was 24 - which I serious doubt. The radiator and TRV were not covered and my normal room temperature is 19/20 so it just wasn't 24. You can add an offset temperature but I decided to wait until I'd fitted it on the radiator I wanted it on.

Next you can find out what temperature the eTRV is currently programmed for and what mode it is in. These are all indicated with various flashes of the yellow, green or red LEDs (you really won't want to lose the manual as you'll never remember all these) e.g., checking the current mode flashes the yellow LED with on for 2 seconds solidly is OFF,1 flash LOW, 2 flashes ECO, 3 flashes COMF and 4 flashes AUTO mode. They have tried to be helpful and put yellow dots on those keys on the hand controller.

From the hand controller you can do a lot:

  • increase, decrease the temperature
  • set various modes (sleep, off, low, eco, comf, auto)
  • move to the next program
  • set the temperature for the various low, eco and conf modes
  • set an offset temperature
  • lock a max/min temperature so someone set a temperature outside those ranges
  • retract or extend the pin for servicing the radiator
  • lock settings on the eTRV itself (the grey button can normally be used to make some changes)
  • boost the temperature for one hour
  • check loads of settings
  • set the day and time
  • program auto mode with 3 on/off settings a day including weekends and weekdays

Programming the eTRV

The eTRV comes with 3 preset programs although none of them match what I wanted.

Programming individual on/off times on the eTRV is a pain in the backside and it is quite easy to press the wrong key at the wrong time. The basic programming sequence is:

  1. Press SET
  2. Press the program (1 - 3) you want to set
  3. press DAY
  4. press one of the day buttons, weekend or weekdays
  5. Press the HOUR button to set the on time then press the number buttons for the time in 24-hour clock
  6. Press the HOUR button to set the off time then press the number buttons for the time in 24-hour clock
  7. Press the TEMP button
  8. Press the button for low, eco or comf
  9. Press the SET button

Whilst you're doing all this you have to watch the LED on the eTRV to a) see if it received the key press and b) to see if it blinks the error code showing you made a mistake. It's not rocket science but quite involved and it is easy to make a mistake. Also, there does not seem to be any way of checking the program once set. Although you can delete a program if you don't sit down and work out what you want before you start you'll get lost and end up having to delete all the programs. In addition, it was not clear to me if you can have a weekday setting and an individual day setting (I doubt you can).

What I don't like about the eTRV

Although it has a reset to factory settings sequence I don't seem to be able to reset it to the point where it was before I first put a battery in i.e., doing a full reset does not put me back to the point in the manual where it does its initial setup. This worries me since I've moved the eTRV onto a different radiator with a different pin length and now I'm not sure if the initial setup does any kind of calibration on the motor (may be it can work out how far it needs to move the pin).

Now to the most irritating thing about the eTRV from my perspective. The marketing says Quiet motorised valve, directly replaces traditional TRV's. I don't know if mine is faulty but it is no where near quiet. The eTRV is around 3 feet from my head when I'm laid in bed. When the motor is running it is very noticeable and now I know exactly when it is 6am every weekday morning. Click on the attachment below for a video of the motor turning (the video is a little shaky - my fault, it is not the etrv shaking):

Your browser does not support the video tag.


Quite a bit quieter now

After running for around 1 - 2 weeks it appears the eTRV is a lot quieter than it was when first fitted. I can still hear it when awake laid in bed but to be fair, I would not say it is disturbing now.