EU Rooftop Solar Cuts Heat, Saves Lives in London

Solar photovoltaic panels now provide more than 17 % of the European Union’s electricity mix, according to Eurostat data for the first quarter of 2026. A 2024 study by researchers at University College London and the University of Exeter, published in *Nature Cities*, estimated that widespread rooftop solar installation could lower London’s ambient temperature by about 0.3 °C during summer heatwaves. The cooling effect would have prevented roughly 96 heat‑related deaths – about 12 % of the fatalities recorded that summer.

The study also found that solar panels keep rooftops about 2.8 °C cooler in daylight, while at night they retain heat, reducing winter heating costs. During a recent June heatwave, a typical UK home with rooftop solar generated enough electricity to run an air‑conditioning unit for five hours per day, amounting to ten million AC‑hours across the 1.9 million solar‑equipped homes each day. Dr. Charles Simpson, lead author, said, "Solar panels have great benefits as a renewable energy source, so it is positive to see they will not make the city hotter." The findings highlight solar power as a complementary technology to air‑conditioning, offering both climate‑mitigation and public‑health advantages.