• Tech Tech

UK study says rooftop solar could have cooled London, and helped prevent 96 heat deaths

Part of the cooling effect is simple: panels shade the roof surface.

A house with rooftop solar.

Photo Credit: iStock

Cutting electricity costs is the usual pitch for rooftop solar, but studies indicate the panels may also help blunt extreme summer heat by slightly cooling buildings and even urban areas.

Modeling from a 2024 paper on Greater London suggested that widespread rooftop solar during the 2018 heat event might have lowered average outdoor temperatures across the city by about half a degree Fahrenheit, according to Techy44.

What's happening?

Published in Nature Cities in 2024, the London analysis estimated 786 heat-related deaths in Greater London during that three-month period.

Under the study's scenario with broad rooftop solar coverage, the researchers estimated that 96 of those deaths, about 12%, might have been avoided.


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Those numbers came from modeling, not from observed deaths directly prevented by existing panels.

Part of the cooling effect is simple: panels shade the roof surface, and the gap beneath them can allow some trapped heat to dissipate.

At a laboratory building, University of California San Diego researchers measured daytime ceiling temperatures about 5°F lower beneath solar panels than beneath an exposed roof, and the roof absorbed roughly 38% less heat.

Eurostat said renewables accounted for 45.5% of electricity generation in the European Union during the first quarter of 2026, up from 42.7% in the first quarter of 2025.

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Why is it important?

Solar may be especially useful during heat waves because its output tends to peak when cooling demand is highest.

Ember estimated that, during a June 2026 heat wave, a typical United Kingdom home with rooftop solar generated enough electricity to run a whole-home air-conditioning setup for around five hours per day.

Because that timing lines up so well, households can cut power bills, reduce some indoor heat gain, and produce cleaner electricity at the same time.

The London study found that highly reflective cool roofs would have delivered a bigger modeled temperature drop, meaning rooftop solar is not a one-size-fits-all solution.

University of California San Diego environmental engineering professor Jan Kleissl said, "There are more efficient ways to passively cool buildings, such as reflective roof membranes."

What's being done?

Factors including roof age and condition, nearby shade, panel layout, warranties, storage choices, and whether a system is owned or leased can all affect how much value solar actually adds.

Tools like EnergySage's solar map can also show the average cost of a home solar panel system in each state, along with local incentives — resources that can help readers get the best price for rooftop solar panels and access available incentives.

EnergySage's free services can also make comparison shopping much easier. With EnergySage's help, the average person can save up to $10,000 on solar purchases and installations. Its quote-comparison tools give homeowners a clearer view of equipment, pricing, and financing before signing a contract.

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