Thermostatic Radiator Valves (TRVs) (illustrated in the image above) control the flow of hot water into radiators and switch off when the room gets up to temperature.

TRVs are often adjusted to their maximum value in many rooms in schools. This means that rooms are often too hot and windows are opened to cool them down which wastes energy. The TRVs are designed to maintain a set temperature and so should generally not be set to maximum. School users also turn them up to maximum when they arrive in the morning if it is cold, under the mistaken belief that the room will heat up quicker. 

We generally recommend that it should be part of the caretaker’s or building manager’s schedule to go around the school every two or three weeks to check the TRVs and set them to a reasonable level. It might also be helpful to discuss with the room users whether the room is too cold at certain times. 

Sometimes, if TRVs have been turned up because it is cold on Monday mornings, it might be worth turning the boiler on two hours earlier for Monday mornings only. 

In some schools with other heating systems, it is not possible to install TRVs but you can often change the configuration of your boiler to include ‘weather compensation’ which turns the temperature of the circulating central heating water down in milder weather and this has a similar effect to TRVs. If this is the case at your school, remember to ask your boiler engineer about ‘weather compensation’ next time they service the boiler. 

Energy Sparks has many pupil activities looking at temperatures in classrooms, for example, carrying out an experiment to monitor classroom temperatures. This is a good way of getting whole school buy-in to maintain reasonable temperatures in school. As a rule of thumb, your heating costs will go up by about 10% for every degree classrooms are above the recommended 18C.