>There are units which exchange heat with water, but typically they won't reach more than 40-45 C°, maybe 50, I doubt 55, so radiators That's what two heating

>There are units which exchange heat with water, but typically they won't reach more than 40-45 C°, maybe 50, I doubt 55, so radiators That's what two heating "experts" told me in Spring 2021 when my gas furnace for central heating needed to be replaced and I asked them wether it would be possible to just replace it with an electric heat pump. "Impossible", they said, your house is not insulated strongly enough and you don't have floor heating, so the outgoing temp will not suffice". It's not true. There are many heat pumps on the market now, and have been since 2020, which manage to deliver 55°C without problem, amongst them, self-contained "monobloc" devices[1] - a box mounted at the outside of the house, which only needs cables and two pipes for connecting to the central heating circulation. With COP values of 3-4 depending on outside temp and outgoing heating water temp. Look at your actual outgoing temp settings (or "heating curve") on the gas furnace. If you never need >55°C, or only need such a temperature on three extremely cold days each year, then a heat pump might be a good idea. Except you can't buy them right now, at least in parts of Europe, for reasons that need not be repeated here. [1] e.g. this one, which even delivers 60°C: https://www.daikin.eu/en_us/product-group/air-to-water-heat-pump-low-temperature/daikin-altherma-3-m.html https://www.daikin.eu/en_us/product-group/air-to-water-heat-...