Make Europe Cool Again<br>In summer, heat kills. 61,672 Europeans died of heat in 2022, ~47,700 in 2023, ~62,800 in 2024, two to three times more than the ~20,000 who die on EU roads. In winter, we wire billions abroad: the EU’s fossil-fuel import bill roughly doubled to €600–700 billion in 2022, and when the Strait of Hormuz closed this March, a fifth of the world’s LNG went offline and every European heating bill got repriced by a war we are not even part of.
The fix already exists: heat pump<br>A year passes. The weather swings. A simulation of the energy needed to keep a house comfortable.<br>heat pump (indoors) passive cooling: compressor OFF, only a small circulation pump (~£20/year) 10 m down: 9–11°C all year a 15 cm borehole ~100m deep<br>outdoor air ground<br>ground to keep warm here, air-source pulls 16 kW from the grid; ground-source 3.9 kW
Air-source COP
Ground-source COP
Play Replay January<br>Ground temps: long-term Central-Europe mean 9.4–11.1°C below ~10 m (Geophysical Journal Intl). COP tiles show measured fleet averages, not spec sheets: air-source field curve from ~550 monitored units with resistive backup below −20°C (Joule 2023); ground-source seasonal COP 4.1 vs 3.1 for air in existing buildings (Fraunhofer ISE). kW = electricity draw for a typical home, space heating only.
A heat pump is simply a two-way air conditioner: cooling in July, heating in January, no imported molecules. It doesn’t make heat, it moves it, so one unit of electricity delivers three to four units of heat. But at roughly 20% AC penetration and with heat pump sales falling, Europe is stuck. I don’t think the answer is another mandate. The answer is making the technology so good and so cheap that adoption becomes the obvious choice, the way electric light beat the gas lamp.
Lighting already made the full journey off gas<br>Light Gas lamp 1861<br>→ Sodium lamp 20th century<br>→ LED LED today
Heat Gas boiler 20th century<br>→ Air-source heat pump today<br>→ Ground-based heat pumps the future mainstream?
Air conditioning saves lives
Air conditioning is treated in Europe as an American indulgence. The data says it is public-health infrastructure. Like a sewage system. The landmark Barreca study found that the spread of residential AC “explains essentially the entire decline” in US hot-day mortality, a 70% drop. During the 1995 Chicago heat wave, a working air conditioner cut the odds of dying by about 70%. Yet only about one in five European households has AC, versus roughly 90% in the US and Japan.
The cost is not only lives. Once temperatures pass 30°C, labour productivity falls about 3% for every additional degree; the 2025 heat waves alone cost Europe around half a point of GDP. Noah Smith is right: the crusade against cooling probably costs far more lives than the saved emissions justify.
The heat pump is a superior two-way AC
Europe’s resistance to cooling made sense once. For most of the 20th century the continent’s summers were mild; a French climate scientist notes that heat like this June’s was “virtually impossible” at that time of year as recently as 1976, and electricity has long cost far more than it does in America. So air conditioning hardened into a symbol of American excess: 8 in 10 French people say AC harms the environment. Then the climate moved and the 2003 heat wave killed more than 70,000 Europeans, roughly 15,000 of them in France in three weeks. France’s response was deliberately minimal: check-in registers for the elderly and one mandatory cooled room per care home. It still cut heat deaths by about 90%. Even a homeopathic dose of cooling worked; Europe just never took the cure to scale.
The device that takes it to scale is not the guilty American box. It is the same machine run both ways: one answer to both of Europe’s problems at once.
Every gas boiler converted removes roughly 12 MWh of imported gas per home per year. Scale that up: about a third of all the gas Europe burns goes to heating buildings, on the order of 100 bcm a year, two-thirds of what Russia supplied before the war. Electrifying heat is the single largest act of energy independence available to Europe, bigger than any LNG deal.
And here is the asymmetry the gas industry cannot answer: gas can make light, poorly. It can make heat, expensively. But it can never make cold. In the century of heat waves, the challenger doesn’t just beat the incumbent at its own game; it plays a game the incumbent physically cannot enter.
Survive the Dunkelflaute
Germany has a word for a stretch of days when the wind dies and the sun barely rises: Dunkelflaute, the dark lull. Wind and solar produce almost nothing for days, handing clean-tech skeptics their favourite proof that carbon is a must-have. On 12 December 2024, in the middle of one, day-ahead power hit €936/MWh, about 12 times the annual average. The regulator found no manipulation: the scarcity was real.
Now add heating. Field data from ~550 heat pumps shows air-source units...