Rooftop solar panels can generate enough electricity to power whole-home air conditioning systems for several hours during sunny periods, according to new analysis. This synergy could help offset the cost of cooling homes during increasingly frequent heatwaves.
The hotter and sunnier the weather, the more electricity solar panels produce. These are also the conditions that require air conditioning systems to work harder. A typical UK rooftop solar installation, researchers found, generated approximately 15kWh of electricity on June 21 and 22. This amount is equivalent to powering a 3kW whole-home air conditioning system for about five hours.
Researchers at the clean energy think tank Ember conducted the analysis, which was based on a typical UK rooftop solar installation. Most UK homes have systems ranging from 4kW to 5kW, often comprising 10 to 12 solar panels. The actual electricity generated depends on factors such as sunshine, roof orientation, and shading.
Running air conditioning without solar power means incurring costs for every unit of electricity consumed from the grid. At an average UK electricity price of 26.11p per kWh, generating 15.2kWh of electricity via solar could save approximately £4 compared to purchasing it from the grid. Over a week-long hot spell with similar sunshine, these savings could amount to around £28.
However, the benefit of solar-powered cooling is most significant when air conditioning is used during daylight hours when the sun is shining. Households that use cooling systems in the evening or overnight may still need to draw electricity from the grid, unless they have a home battery to store excess solar power.
As the UK experiences more frequent hot spells, the Climate Change Committee has previously stated that nearly a quarter of UK buildings could require active cooling in a world that warms by 2C. For homeowners considering installing air conditioning or air-to-air heat pumps, solar power could become a more significant factor in their financial calculations.
The cost of a professionally installed 4kW to 5kW solar panel system suitable for many UK homes can run into several thousand pounds, with smaller systems and DIY kits being less expensive. Similarly, a fully installed, multi-room air conditioning system in the UK typically costs between £3,000 and £6,500 or more for a standard family home.
For homeowners with solar panels, there is also the option to export excess electricity back to the grid through special export tariffs. For instance, the Outgoing Octopus tariff pays 12p per kWh for exported units. This offers an additional financial benefit alongside offsetting home energy consumption.