What temperature control actually saves — from thermostat to zones
Room thermostat
Basic automation: the boiler switches on at a set temperature, not 'at max'. Saves 10–15% of gas/electricity for heating.
Weekly schedule
Different temperatures: nights −3°C, home days +21°C, away +15°C. Another 5–10% saved — heating an empty home at full is a typical loss.
Thermostatic radiator valves
TRV on each radiator: bedroom 18°C, living room 21°C — separate zones without overheating. Pays back in a season in overheated rooms.
Smart zones
Actuator valves per room/floor + central controller. Makes sense with 3+ rooms on different schedules; payback 2–4 seasons.
Weather-compensated control
Outdoor temperature sensor → boiler heats water exactly as much as needed. Most effective for condensing boilers and underfloor heating.
Remote control
App: turn heating on an hour before returning home. Simpler than constant temperature and cheaper than 'heating everything just in case'.
Payback rule: thermostat and schedule first (cheapest, biggest effect), then TRVs on problem rooms, zones in large homes. Each −1°C of average temperature is ~6% of heating energy. Savings estimates are approximate and depend on insulation.