Your questions
Your questions
People planning a heat pump, solar panels or a battery keep asking the same few things. I pick the ones that come up most, run one house through the simulation for a year, and answer with a short video and the numbers behind it.
Oil boiler or heat pump, now vs. 2025
Heating oil costs 1.93 EUR a litre in France and 1.71 in Germany, and a heat pump looks like the obvious way to cut the bill. Would it still pay if oil fell back to its 2025 price? In France, yes, clearly: at the 2025 average the heat pump still saves 674 EUR a year, and it stays cheaper to run until oil falls to 0.62 EUR a litre, a little over half that average. In Germany the 2025 price leaves a saving of 188 EUR a year, a payback of 127 years even after the grant, so there the answer depends on oil staying high.
Read the answerDoes a bigger heat pump use more electricity?
Barely: on a new house in Würzburg, a 16 kW heat pump used about 70 kWh (18 EUR) a year more than the 10 kW unit that the sizing proposed, and started about 40 percent more often. Too small is what costs money: a 4 kW unit cost about 320 EUR a year more, through its electric backup heater.
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