Smart Thermostat Savings Calculator
Find out how much a smart thermostat saves you per year — and how fast it pays for itself.
Want to reduce heat loss first? Heat Loss Calculator → | Insulation Savings Calculator →
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Tip: Each 1°C setback saves roughly 6–8% on heating. A 3°C setback can cut your bill by up to 24%.
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Savings estimated using the 6% per °C per hour rule — a well-established approximation for typical European climates. Actual savings vary by insulation, climate and heating system.
Common questions about smart thermostat savings
How much does a smart thermostat save per year?+
A smart thermostat typically saves 10–23% on heating bills. For an average European household spending €1,200/year on heating, that is €120–€275 per year. The exact saving depends on your setback temperature and how many hours per day the home is unoccupied or you are sleeping.
How long does a smart thermostat take to pay for itself?+
Most smart thermostats cost €100–€300 installed. At €150–€250 annual savings, payback is typically 1–2 years. After payback the savings are pure money in your pocket every year for the 10–15 year lifespan of the device.
What temperature setback saves the most?+
Each 1°C reduction saves approximately 6–8% on heating costs. A 3°C setback (e.g. from 21°C to 18°C) saves roughly 18–24%. Larger setbacks save more but take longer to reheat — smart thermostats learn your schedule and pre-heat so the home is comfortable when you arrive.
Does a smart thermostat work with a heat pump?+
Yes, but with a caveat: heat pumps are most efficient at a steady low flow temperature. Large setbacks force the heat pump to work harder to recover, reducing COP. For heat pumps, a smaller setback of 1–2°C over longer periods is more efficient. Always check thermostat compatibility with your heat pump brand.
Which smart thermostat saves the most energy?+
Nest Learning Thermostat, Ecobee SmartThermostat and Tado° consistently rank highest. Nest claims 10–12% heating savings, Ecobee reports up to 23%. The best choice depends on your heating system type and compatibility — check before buying.
How smart thermostat savings are calculated
The method
Heating energy use is roughly proportional to the temperature difference between inside and outside (Newton's law of cooling). Lowering your thermostat by 1°C when away reduces the temperature difference driving heat loss — and therefore your heating energy — by approximately 6% of your total bill per degree per hour of setback, averaged over a heating season.
The formula
Saving rate = setback (°C) × 6% × (setback hours / 24). Applied to your annual heating bill, this gives an annual saving estimate consistent with real-world studies from Nest, Ecobee and academic sources.
Heat pump caveat
Heat pumps run at a lower efficiency (COP) when recovering from deep setbacks. This calculator applies a 40% discount to the saving rate for heat pump systems, reflecting the reduced benefit of large temperature swings.