How do I set my heating timer and thermostat properly?

Three controls interact: the timer decides when, the room thermostat decides whether, and the radiator valves decide where. Most wasted heating comes from using one of them to do another's job.

What you'll need

• Your heating controls
• The manual (optional)

Step by step

1. Set the room thermostat to your target temperature.Typically 18-21°C for living areas. Each degree higher adds meaningfully to the bill, so find the lowest comfortable setting.
2. Understand that the thermostat is not a throttle.Setting it to 25°C does not heat the room faster. The boiler runs at the same output either way; it just runs for longer and overshoots.
3. Use the timer for when heating is available.Set it to come on shortly before you need it and off before you leave or sleep. Houses hold heat for a while after the boiler stops.
4. Start the heating 30 minutes before you need it.Most houses take that long to reach temperature. Adjust based on how yours actually behaves over a few days.
5. Set thermostatic radiator valves per room.Lower in bedrooms and hallways, higher in living rooms. The numbers are relative settings, not temperatures.
6. Leave the radiator in the thermostat's room fully open.If that radiator is throttled, the thermostat never reads the true room temperature and the whole system misbehaves.
7. Set a lower overnight temperature rather than switching off entirely.Around 15-16°C. It costs less than reheating a cold house and prevents condensation and frozen pipes.
8. Check the thermostat's position.In a draught, above a radiator, or in direct sun, it reads wrongly and either overheats or underheats the whole house.

Tips

• A smart thermostat's main benefit is not remote control but learning how long your house takes to warm, and not heating an empty house.
• Set the hot water separately from the heating. Heating water all day when you shower once is a common and avoidable waste.
• Bleeding radiators and balancing the system makes a bigger difference than any control setting if some rooms never get warm.

Common mistakes

• Turning the thermostat up to heat the house faster — It does not work that way. The room heats at the same rate and then overshoots your intended temperature.
• Throttling the radiator in the thermostat's room — The thermostat then reads cold and keeps the whole house heating far beyond what you wanted.
• Turning the heating off completely when away in winter — A frost setting costs little and prevents frozen pipes and damp, both of which are far more expensive.

Questions people ask