Thermostatic radiator valves, or TRV’s, should be fitted to all but 1 radiator in the house. They are a sensor that detects the air temperature and when the desired air reaches temperature is reached then they close the flow to the radiator. When the temperature in the room drops then the sensor opens up re-establishing flow to the radiator that it is on. The TRV only shuts off the radiator that it is installed on so if there are rooms that have multiple radiators then each radiator will need to have its own TRV. TRV’s do not turn off the boiler. TRV’s can be set to different temperatures in different rooms, so if there was a room in the house that was used less than others then normally it would be on a lower setting when compared to a room that is used frequently, such as the living room. As mentioned TRV’s should be on every radiator in the house, and it is building regulations that on any new installation this should be carried out, with the exception of 1 radiator. The one radiator that doesn’t have a TRV installed on is the radiator in the same room as the room thermostat and if there is a TRV on that radiator then it should be set to the maximum setting. The idea of this is when the room that the room thermostat is in reaches the desired temperature that will turn the boiler off.

More modern TRV’s are going electrical now, powered by batteries, and these are linked wirelessly to a receiver, with this receiver wired into the boiler. The difference with these kind of TRV’s though is that they are installed on every radiator. The idea is that you can set each room to the desired temperature and, as with a traditional TRV, it will close off the flow to that individual radiator when the target temperature is reached. However when all the TRV’s have reached the desired temperature then the wireless receiver knows that the house is hot enough and sends a signal to the boiler to shut it down.

There is no right or wrong setting for a TRV, be it a traditional one or an electrical one, it is very much down to the users comfort level and also how they use the house. They are a very economical way to control the temperature in a room, however due to the height that they are installed at, which is normally just above the top of a skirting board, they don’t really detect the temperature where a person body or head is, just there lower leg/ankle, so if a TRV was set to say 20˚c it may be closer to 22˚c where the persons body is, so it maybe that you set the TRV lower in order to achieve a lower room temperature