With a seasonal COP of 3.39, the heat pump would cost about 1,180 €/yr to run, 445 € less than your current heating. It stays cheaper as long as electricity costs less than 3.9× your fuel price per kWh (now 2.8×).
Heat pump running cost
€1,180
4,214 kWh of electricity per year
Seasonal COP (SCOP)
3.39
heating + hot water, weather-compensated 45 °C flow
Current heating cost
€1,625
16,253 kWh of fuel at 88% efficiency
Annual saving
€445
Heat demand
14,303kWh/yr
102 kWh/m²·yr incl. hot water
Design heat loss
5.5kW
at -9 °C outdoor
Heat pump size
5.5kW
suggested nominal output
Backup heater share
0%
2 kWh from the immersion/backup heater
CO₂ saved per year
1.5t
1.47 t vs 2.97 t now
Break-even price ratio
3.86
electricity ÷ fuel price per kWh
Simple payback
31 yr 5 mo
Heating degree days
2,418K·d (base 15.5 °C)
Berlin, Germany
Month by month
| Month | Mean °C | Heat (kWh) | Electricity (kWh) | COP | Cost (€) |
|---|---|---|---|---|---|
| Jan | 0.6 | 2,508 | 836 | 3 | 234 |
| Feb | 1.4 | 2,152 | 700 | 3.07 | 196 |
| Mar | 4.8 | 1,852 | 534 | 3.46 | 150 |
| Apr | 9.6 | 1,074 | 261 | 4.12 | 73 |
| May | 14.2 | 512 | 118 | 4.33 | 33 |
| Jun | 17.5 | 263 | 66 | 3.99 | 18 |
| Jul | 19.6 | 210 | 55 | 3.82 | 15 |
| Aug | 19.2 | 217 | 57 | 3.83 | 16 |
| Sep | 15.1 | 414 | 97 | 4.27 | 27 |
| Oct | 10 | 1,050 | 252 | 4.16 | 71 |
| Nov | 5.2 | 1,731 | 492 | 3.52 | 138 |
| Dec | 1.8 | 2,320 | 745 | 3.11 | 209 |
- Climate: Berlin, Germany (1991–2020 normals, approximate). Day-to-day temperature spread is modelled with ±3.5 K bins.
- COP model: a fraction of the Carnot limit with 3 K condenser and 5 K evaporator approach, plus a defrost penalty around 0 °C. Field-measured SPFs typically come in 0.2–0.5 below lab ratings when systems are poorly commissioned.
- Hot water is assumed at ~1.6 kWh per person per day, plus 1 kWh/day of cylinder loss.