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Heating and central heating

Heating Controls Explained

Good controls make heating more comfortable and less wasteful. Most systems use a combination of three things: something to set times, something to set temperature, and something to control each room.

3 min read · Updated October 2026

Heating programmer, room thermostat dial and thermostatic radiator valve mounted on a wall

Timer or programmer

A programmer switches the heating – and on some systems the hot water – on and off at set times. Programmers range from simple mechanical dials to digital units with different times for weekdays and weekends.

Room thermostat

A room thermostat switches the heating off when the room reaches the temperature you've chosen, and back on when it cools. It only works during the times the programmer allows. Many modern units combine the programmer and thermostat in one.

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Radiator valves and other controls

Thermostatic radiator valves (TRVs) adjust each radiator to keep its room near a chosen setting. Systems with a hot water cylinder also have a cylinder thermostat and motorised valves that direct hot water where it's needed. Some boilers also offer weather compensation, which adjusts the water temperature to the weather outside.

  • Programmer: when the heating can run
  • Room thermostat: how warm the main living space gets
  • TRVs: how warm each room gets
  • Cylinder thermostat: how hot stored water gets

Common questions

Should I set the room thermostat or the TRVs?

Both. Set the room thermostat for your main living area and use TRVs to fine-tune other rooms.

Should the radiator near the thermostat have a TRV?

Usually that radiator is left on a manual valve, so the two don't work against each other. Your engineer will advise.

Can old controls be upgraded without a new boiler?

Often yes, as long as the new controls are compatible.

Keep reading

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A smart thermostat lets you control your heating from your phone and can adjust itself to your routine. Here's what to expect and what to check before buying.

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TRV numbers explained

Thermostatic radiator valves don't set how hot the radiator gets – they set how warm the room should be. Here's how to use the numbers.

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Heating zones explained

Zoning splits a home's heating into areas with their own controls, so you can heat upstairs and downstairs – or an extension – at different times and temperatures.

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