A TRV attaches to your radiator to control the temperature in that room. It adjusts the amount of hot water flowing into the radiator based on whether the air around it is hotter or colder than your chosen setting. They only work when the boiler is already supplying hot water.
Most TRVs are manual – you turn a dial to adjust the valve to your chosen setting. We have reviewed a new, digital type of TRV.
How much control?
TRVs are useful if you don't use all the rooms in your house regularly. With manual TRVs, you can adjust the level of heat you want but you can't choose an exact temperature.
Start by putting your TRV on a low setting and then turn it up until you feel comfortable. You can also use them to keep the heating low in rooms you don’t use.
- Dials on manual TRVs. Some click into position, but others are continuous – so you may have to remember positions or add your own tactile markings. They can be stiff, but some models come with added gripping aids (see picture).
Pegler i-Temp i30 (£25)
This is a new type of digital TRV. You can set the temperature you'd like the room to be, as well as setting times for it to come on and off each day.
- The screen is difficult to see. The temperature is in large figures, but other information is very small.
- The dial is continuous, so you can't feel what setting it's on.
- There is no sound feedback.
- It would require instructions and probably sighted help to programme it.
- Some testers liked the idea of having more control, but most would prefer a traditional manual TRV.
Who is this suitable for? People with some useful sight who want a lot of control over how each room is heated, and can get help with initial set-up.
Score: 2 out of 5
We last tested TRVs in 2004. You can see the results of those tests in our previously tested section.
Last updated: February 2014
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