Heating Temperature Reduction Savings Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/9/2026
Lowering the heating's set temperature by one degree saves about 7% of the annual heating cost, according to French agency ADEME. For an annual cost of €1,500, lowering it by 1°C saves about €105 a year.
Explanation
ADEME and many energy specialists regularly cite a simple benchmark: each degree the heating's set temperature is lowered saves about 7% of the annual heating bill. This figure comes from the fact that a home's heat losses (through walls, windows, roof) are broadly proportional to the gap between indoor and outdoor temperature: reducing that gap mechanically reduces the amount of energy needed to keep the home at the chosen temperature. This 7% benchmark nonetheless remains an approximate average, not an exact physical law applying identically everywhere: ADEME itself states a range of 5 to 10% depending on the home's characteristics (insulation, region, heating system), and the approximation becomes less reliable beyond 2 to 3 degrees of reduction, where other effects (occupant behavior, comfort thresholds) come into play in a less linear way. This calculator applies this 7%-per-degree benchmark to your own annual heating cost, to give a realistic order of magnitude rather than a figure guaranteed to the cent. To estimate your starting annual heating cost from your energy need, see our heating cost comparison calculator; for the cost of another electrical appliance rather than heating, our electricity cost calculator.
Example: a €1,500/year cost, a 1°C reduction
Inputs
Annual heating cost: €1,500. Reduction considered: 1°C.
Calculation
Savings = 1,500 × 0.07 × 1 = €105. New cost = 1,500 − 105 = €1,395.
Result
This 1°C reduction saves about €105 a year, for a new cost of about €1,395.
Frequently asked questions
Where does this 7%-per-degree benchmark come from exactly?
It rests on the physical principle that a home's heat losses are broadly proportional to the gap between indoor and outdoor temperature: the smaller that gap, the less energy is needed to offset it. ADEME and several energy organizations cite this figure as a representative average, without claiming universal precision applicable to every home.
Is this percentage valid for any number of degrees of reduction?
No, this benchmark stays reliable for a moderate reduction (generally 1 to 3°C), where the link between temperature gap and heat loss stays roughly linear. Beyond that, the estimate becomes less reliable: other factors come into play (actual occupant behavior, heating systems that don't react in a perfectly linear way), which is why this calculator deliberately caps the input at 3°C.
Is this saving the same for every home?
No, ADEME itself states a range of 5 to 10% depending on the home's characteristics: a poorly insulated home or one in a region with a harsh climate can noticeably deviate from the 7% average used here, in either direction. This calculator gives an order of magnitude based on the most commonly cited average, not a guaranteed measurement for your specific home.