What does a Room Thermostat Do?

A room thermostat is an electrical switch that controls the temperature of a room.
It is also called a roomstat and it is one of the heating controls of a central heating system.

The room thermostat is set to a particular temperature. It senses the
air temperature and turns the boiler on or off to keep the room at the set temperature.
The room thermostat will only work when it is turned on by the programmer.
Some room thermostats are wireless and some are connected directly to the wiring centre.

Turning the room thermostat up will make the room heat up to a higher temperature but it will
not make the room heat up more quickly. The rate at which the room heats up depends
on the boiler, radiator size, room size and the amount of insulation in the roof and walls.
Turning the room thermostat down will maintain the room at a lower temperature
(using less energy and saving you money) but it will not make the room cool down more quickly.
The rate at which the room cools down depends only on the amount of insulation.

To work well, the room thermostat needs a free flow of air and should not be covered
by curtains or furniture. It should also not be near other heat sources.
For most central heating systems only one room (usually the hall) has a room thermostat.
The room thermostat is sometimes found inside the programmer.
To have different rooms at different temperatures, the radiators can be fitted with TRVs.
The radiator nearest to the room thermostat should not be fitted with a TRV.