Before you start programming, familiarise yourself with the modes your thermostat supports. Most programmable and smart thermostats offer:

• Comfort mode — your target temperature when the house is occupied and awake (typically 19–21°C).
• Setback / Eco mode — a reduced temperature used at night or during unoccupied periods (typically 15–17°C).
• Away mode — a frost-protection temperature (12–14°C) used when the house is empty for extended periods.
• Boost / Override — a temporary override that raises the temperature for a set duration (1–3 hours) without changing the underlying schedule.
• Holiday mode — similar to away mode, but set for a fixed number of days.

Not all thermostats have all of these, but the more modes available, the more precisely you can tailor your heating.

The key to good thermostat programming is matching the temperature to what you actually need at each time of day. Here are evidence-based recommendations:

• Morning warm-up (e.g. 06:30–08:00): set to your comfort temperature — 20°C for living areas, 18°C for bedrooms. Programme the heating to start 30 minutes before you get up, as most systems take time to reach setpoint.
• Daytime when occupied (08:00–17:00): if someone is at home, maintain comfort temperature. Use room-by-room temperature guidelines — a home office needs 20°C, a kitchen only 18°C.
• Daytime when empty (08:00–17:00): drop to setback temperature (16°C). Every degree lower saves approximately 7% on your heating fuel — an empty house heated to 16°C instead of 20°C saves roughly 28% during that period.
• Evening (17:00–22:30): return to comfort temperature for occupied living areas.
• Night (22:30–06:30): setback to 16°C. Most people sleep comfortably with 18°C in the bedroom and a lower temperature in the rest of the house.

Modern programmable thermostats allow different schedules for different days of the week — a feature well worth using. A typical household benefits from:

• Weekdays: full setback during working hours (08:00–17:00), comfort morning and evening.
• Saturday: comfort from a later morning start, continuous through the afternoon.
• Sunday: similar to Saturday, or with a slightly earlier evening setback if everyone retires early.

If your thermostat only supports a 5/2 or 7-day schedule, choose the option that best matches your routine. A 7-day schedule is always preferable if available.

Use our free thermostat calculator to calculate the exact savings for your specific schedule.

Your thermostat is only as accurate as its environment. Before relying on any programmed schedule, check that:

• The thermostat is mounted at roughly 1.5 metres height — not on the floor (cold) or near the ceiling (hot).
• It is not placed in direct sunlight, which causes it to read the room as warmer than it is and under-heat the space.
• It is not near a radiator, cooker, or any other heat source.
• The radiator in the same room as the thermostat is fully open and not thermostatic — the system uses this room as the reference point.
• There are no draughts from doors or windows blowing cold air directly onto the sensor.

One of the most common programming mistakes is forgetting to activate away mode when leaving the house for more than a few hours. Keeping a house at 20°C while everyone is at work or school for 8 hours a day is one of the biggest sources of wasted energy in the home.

• Use away mode for any absence longer than 3–4 hours.
• Set the away temperature to 14°C — this protects pipes from freezing in cold weather and is much cheaper than maintaining comfort temperature.
• On smart thermostats, geofencing automates this: the thermostat detects when your phone leaves the house and switches to away mode automatically.
• For holidays, use the dedicated holiday mode if available, which maintains frost protection for a set number of days before reverting to the normal schedule.

No initial programming is perfect. After living with your schedule for a week, ask yourself:

• Is the house too cold when you get up? Move the morning start time 20–30 minutes earlier.
• Is the house already warm before the comfort period starts? Your boiler is faster than you thought — delay the start by 15 minutes.
• Are you regularly using the boost function? If so, consider adjusting the relevant period's temperature up by 1°C rather than overriding repeatedly.
• Is the house warm enough in the evening? Check for draughts and insulation issues before increasing the setpoint — adding 1°C costs roughly 7% extra fuel.

See also our energy-saving tips and seasonal thermostat guide for adjusting settings as the weather changes throughout the year.