Soaring Temperatures Raise Concerns Over UK’s Cooling Demand: Report

The United Kingdom (UK) recently experienced soaring temperatures as a week-long heatwave swept across Europe in late June 2026. According to a recent report by Ember, a typical UK home with rooftop solar generated enough electricity during the heatwave to power the equivalent of more than five hours of air conditioning per day.

The June 2026 heatwave highlighted the complementary nature of solar power and active cooling. During the first days of the heatwave, which coincided with the summer solstice, UK homes with solar panels generated the equivalent of five hours of self-supplied air conditioning each day.

Although air-conditioning use tends to be concentrated later in the day, solar generation and cooling demand broadly follow similar seasonal patterns. On 21 and 22 June 2026, a typical UK rooftop solar installation generated 15 MWh, equivalent to five hours of electricity demand from a full-house air-conditioning system rated at 3 kW per day.

The UK Met Office issued a Red Extreme Heat Warning for parts of England and Wales on 24 and 25 June 2026, with temperatures forecast to exceed 37°C. This upgraded an Amber warning that had been in place since 22 June. As heat-related risks become more significant, active cooling technologies such as air conditioning are receiving increasing attention.

While passive cooling remains an important climate adaptation measure, the Climate Change Committee’s 2026 Independent Assessment of UK Climate Risk suggests that nearly a quarter (22%) of UK buildings will require active cooling in a future with 2°C of warming. The report also projects a 70% increase in the number of days when temperatures in English schools reach 35°C. Although adoption of both passive and active cooling remains relatively low, the need for such measures is becoming increasingly urgent.

UK Installs more than 2.5 GW solar capacity in 2024, 2025

The report found heatwave has struck UK at a time when its installed more touches than 2.5 GW of solar capacity in both 2024 and 2025. This, the report found exceeds the total capacity installed between 2017 and 2021. Rooftop solar installations have also increased significantly in recent years despite the absence of direct government subsidies.

The UK has entered what Ember describes as its second solar boom. The country’s peak half-hourly solar generation record was broken eleven times in the first half of 2026 alone, the highest number recorded in a single year since 2016. Rooftop solar was installed at a record annual rate in 2025, with 2026 on track to surpass that level.

Its recent solar deployment has created significant potential for cost-effective cooling, with solar generation helping to meet rising electricity demand from active cooling technologies such as air conditioning. Solar generation and air-conditioning demand follow similar seasonal patterns, making the two technologies complementary. Across the UK’s 1.9 million homes with rooftop solar, the equivalent of 10 million solar-powered air-conditioning hours were generated during each day of the heatwave.

Britain Entered Its Second Solar Boom

Britain has now entered its second solar boom. During the first phase of solar expansion, supported by the Feed-in Tariff and Renewables Obligation schemes, around 10 GW of solar capacity was installed within five years from 2012.

This was followed by a period of slower growth. Over the subsequent five years, less than 2.5 GW of solar capacity was installed as subsidies were phased out. However, following energy market volatility driven by international fossil fuel crises, solar deployment has accelerated again despite the absence of household subsidies. More than 2.5 GW of solar capacity was added in both 2024 and 2025, exceeding the total capacity installed during the 2017–2021 period.

The renewed pace of deployment is reflected in record generation levels. The peak half-hourly solar generation record was broken eleven times in the first half of 2026 alone, the highest number recorded in any year since 2016.

By the summer solstice on 21 June, total solar generation in 2026 was 2% higher than in 2025, which itself was a record-breaking year, with generation 30% above 2024 levels. UK solar generation exceeded 16 GW for the first time in 2026, more than 50% higher than during the 2022 energy crisis.

Rooftop Solar Expands, Creating Potential For Cost-Effective Cooling

Current rooftop solar deployment already represents significant cooling potential. Across the UK’s 1.9 million homes with rooftop solar, the equivalent of 10 million solar-powered air-conditioning hours were generated during each day of the heatwave.

Rooftop solar generation supports a range of household electricity needs. At the same time, the growing adoption of home battery systems is helping households maximise the use of solar energy throughout the day. Monthly home battery installations doubled between 2024 and 2025, according to data from the Microgeneration Certification Scheme database.

This trend coincides with accelerating solar deployment. Households are installing rooftop solar at the fastest rate on record, with 253,500 domestic-scale installations completed in 2025 alone. The pace has continued to increase in 2026, with installations during the first four months of the year running 3% above the corresponding period in 2025.

The expansion is not limited to household systems. A substantial pipeline of solar farms is also under development through the government’s Contracts for Difference scheme. Although only 854 MW of solar capacity has been commissioned under the scheme so far, a further 10,343 MW has been contracted and is expected to be built before the early 2030s.

Higher Summer Electricity Demand Could Benefit The Grid

Air conditioning may also provide benefits to the UK electricity grid by increasing and shifting demand during periods of high solar generation. In its 2026 Summer Outlook, the National Energy System Operator (NESO) highlighted expectations of surplus electricity during the summer months.

To address this, NESO plans to use its Demand Flexibility Service, which rewards consumers for increasing electricity consumption during periods of excess supply. Even households without rooftop solar can benefit from these flexibility payments by increasing electricity use during reward periods, including by using air conditioning.