Thermostatic Radiator Valves are energy saving and environmentally friendly. Thermostatic radiator valves (TRVs) make it possible to control the temperature in your room quickly and easily. Simply set the temperature that you desire and radiator will automatically reach the required heat output. The heat sensitive mechanism will adjust to the room temperature and alter the amount of hot water that it allows into the radiator, keeping your home at a comfortable and constant temperature.