Regulating valves are generally the most common type of radiator valve and they work in a very similar way to a tap. When the heating is turned on via the boiler or thermostat it allows the heated water to travel through your pipework and reach the valve, prior to entering the radiator. When open the radiator will start to heat, if an individual room has it has reached the desired temperature but other rooms in your home are still warming up then you can simply turn off the valve.
Thermostatic valves allow for further temperature control and may lead to a reduction in energy consumption. Thermostatic radiator valves measure the temperature in the room and then adapt the heat output of the radiator. When the room temperature reaches the desired level the valve closes to stop water flow meaning you won’t be heating the room to a higher temperature than necessary and will reopen once the temperature lowers below the desired level.