Thermostatic radiator valve – Wikipedia
Does turning boiler temperature down save money?
Even if you have your heating on for most of the day, lowering the flow temperature will still help reduce your energy bills as you will be having lower temperatures for longer periods.
Is it better to keep heating at a constant temperature?
Regardless of whether you choose to turn your heating on and off, or keep it on at constant low level, minimising the amount of heat lost from your property through better insulation is always good idea. In the long run, doing so will help you save on bills and cause less harm to the environment.
What temperature should my radiators be?
Typically, the common rule for radiator temperature control is to aim to have each room somewhere between 18C (64F) and 21C (70F). In most homes, these central heating settings should be comfortable, and for others, only slight adjustments would normally need to be made to achieve a preferable temperature.