The electric heat pump

technology

A refrigeration cycle run in reverse, and the most thermodynamically favourable substitution available anywhere in the energy transition. A heat pump does not make heat; it moves heat from a colder outdoor reservoir to a warmer indoor one using work, which is why the ratio of heat delivered to electricity consumed — the coefficient of performance — is greater than one. Real installed systems deliver seasonal coefficients in the range of roughly two and a half to four, meaning three or so units of heat per unit of electricity, against a condensing gas boiler that cannot exceed one and in practice returns a little under it. The efficiency falls as the temperature lift rises, which is why performance is worse in the coldest weather and why radiator-based retrofits perform less well than underfloor systems designed for lower flow temperatures — but the ceiling is the Carnot relation, not a manufacturing limit, and cold-climate machines operate satisfactorily well below freezing. Norway has the highest household penetration in Europe. The instructive thing about heat pumps is that they are the sector where the physics is entirely settled and the deployment is not: European sales fell in 2023 and then sharply again in 2024 on the European Heat Pump Association's market data, driven by electricity-to-gas price ratios, subsidy withdrawal and installer capacity rather than by any technical problem.

A technology is not a place. Drawing it on a map would assert something about the world that no stored fact supports.