Over 15 years the heat pump costs about 1,668 € less in total, overtaking the boiler after 12.7 years, and saves 1.1 t CO₂ per year.
15-year cost difference
€1,668
heat pump cheaper overall
Heat pump running cost (yr 1)
€1,200
3,750 kWh electricity + service
Gas boiler running cost (yr 1)
€1,563
13,333 kWh gas + service + standing charge
Annual running saving
€363
Extra upfront cost
€6,500
heat pump 10,000 vs boiler 3,500
Break-even year
12 yr 9 mo
Your price ratio (elec ÷ gas)
2.8
Break-even price ratio
3.77
running costs equal (pure energy: SCOP ÷ η = 3.56)
15-yr TCO heat pump (NPV)
€25,161
discounted at 4%
15-yr TCO gas boiler (NPV)
€24,489
CO₂ heat pump
1.31t/yr
CO₂ gas boiler
2.44t/yr
17 t saved over 15 yrs
Year-by-year costs (nominal)
| Year | Heat pump (€) | Gas boiler (€) | Cum. HP (€) | Cum. gas (€) | HP advantage (€) |
|---|---|---|---|---|---|
| 1 | 1,200 | 1,563 | 11,200 | 5,063 | -6,137 |
| 2 | 1,224 | 1,609 | 12,424 | 6,672 | -5,752 |
| 3 | 1,248 | 1,656 | 13,672 | 8,328 | -5,344 |
| 4 | 1,273 | 1,705 | 14,946 | 10,033 | -4,913 |
| 5 | 1,299 | 1,754 | 16,245 | 11,787 | -4,458 |
| 6 | 1,325 | 1,806 | 17,570 | 13,593 | -3,977 |
| 7 | 1,351 | 1,859 | 18,921 | 15,452 | -3,470 |
| 8 | 1,378 | 1,913 | 20,300 | 17,365 | -2,935 |
| 9 | 1,406 | 1,969 | 21,706 | 19,334 | -2,372 |
| 10 | 1,434 | 2,027 | 23,140 | 21,360 | -1,779 |
| 11 | 1,463 | 2,086 | 24,602 | 23,446 | -1,156 |
| 12 | 1,492 | 2,147 | 26,095 | 25,593 | -501 |
| 13 | 1,522 | 2,210 | 27,616 | 27,803 | 187 |
| 14 | 1,552 | 2,275 | 29,169 | 30,078 | 909 |
| 15 | 1,583 | 2,342 | 30,752 | 32,420 | 1,668 |
- Replacements: any equipment that reaches the end of its life inside the comparison period is bought again at today's price.
- Maintenance grows 2%/yr and energy prices at the rates you set. Grants are deducted from the heat pump cost in year 0.
- If you keep the gas connection (for cooking, say), you pay the standing charge in both cases and it doesn't affect the comparison.