Heatwaves are dangerous but they’re also a useful warning of what needs to change

As another heatwave reaches the UK, it is worth asking an uncomfortable question: is there any positive side to extreme heat?

The answer is not that heatwaves are good. They are not. They put pressure on people’s health, homes, schools, transport and the electricity grid. The UK Health Security Agency estimated 1,504 heat-associated deaths in England during five heat episodes in summer 2025. The official advisory Climate Change Committee has also warned that 92% of existing UK homes could be at risk of overheating by 2050. So the starting point is clear: heatwaves are a serious climate and public-health risk.

But heatwaves also expose something important. They show us how poorly prepared our homes and energy systems are for the climate we are now living in. In that sense, the opportunity is not in the heat itself. The opportunity is in using heatwaves as a trigger to redesign how we cool, power and protect our buildings.

One obvious route is solar energy. Hotter weather does not automatically mean better solar performance. In fact, solar panels lose some efficiency as they get hotter, with typical losses of around 0.4%–0.5% per degree Celsius. But heatwaves often come with long periods of strong sunlight, and that creates a practical opportunity: using solar power to meet some of the extra demand for cooling.

We should not simply respond to heatwaves by buying more portable air-conditioning units and adding pressure to the grid. During the late June 2026 heatwave, Great Britain’s electricity system operator had to request extra power as households used more fans and air conditioning. That is a warning sign. Cooling is becoming an energy-system challenge, not just a question of household comfort.

Cooling with clean energy

The better response is to connect cooling with clean energy. Homes with solar panels, batteries, external shading, good ventilation and smart controls can use daylight hours more intelligently. Solar power can run fans, heat pumps or efficient cooling systems during the day. Batteries can store surplus electricity for the evening, when demand often rises. Thermal storage can also help by storing coolness or heat, reducing the need to draw electricity at peak times.

This is not a fantasy. Solar power is able to directly meet around half of the world’s cooling demand according to one model, and more when combined with cold thermal storage, such as freezing water when solar electricity is abundant, and using the ice later for cooling. The UK is not directly comparable with the hotter countries covered in that study, but the principle still matters: as cooling becomes more necessary, it becomes more important to power that cooling through clean energy rather than adding pressure to the grid.

There is also a role for heat pumps, especially reversible systems designed for both heating and cooling. The UK government has already framed some heat-pump and heat-battery technologies as tools that can keep homes warm in winter and cool in summer. But this needs careful design. Not every heat pump installation will provide effective cooling, and not every home is ready for it.

The simplest solutions should come first: external shading, trees, better insulation, ventilation, reflective surfaces and one safe cool room in vulnerable homes. These are not glamorous technologies, but they reduce heat before households need to use electricity. Then, where active cooling is needed, it should be efficient, low-carbon and linked to smart energy systems.

The fairness issue is crucial. Wealthier households can adapt first: solar panels, batteries, shutters, heat pumps and better insulation. Renters, older people, low-income families and people in poor-quality housing may be left with the highest heat risk and the least ability to respond. Heatwave resilience therefore cannot be treated as a private luxury. It needs to become part of basic infrastructure.

So yes, there is a positive side to heatwaves but only if we define it carefully. Heatwaves are not good news. But they are increasingly clear warnings of where the system is failing and where investment should go next: cleaner cooling, better homes, smarter storage and a fairer approach to climate adaptation.

Narmin Nahidi does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.