21st June 2026 – This Sunday is the summer solstice, the longest day of the year expected to bring an average of nearly 17 hours of daylight to the UK . Such increased daylight is the perfect opportunity for homeowners and businesses to generate maximum sustainable energy, with conservative estimates projecting a 20% to 60% increase from the June daily average.
For context, a standard 4 kWp solar system could see homeowners generate 24 kWh across the day and break even on their daily energy costs. Similarly, large-scale commercial premises could leverage a 500 kWp solar system into 3,000 kWh of sustainable energy, enough to power all machinery and facilities. While such estimates are exciting, they are only achievable if solar panels are optimised for efficiency.
After a dry spring, characterised by southerly winds blowing saharan dust up to our shores, energy generation could be severely impacted. When dirt settles on solar panels, it reduces their efficiency and can decrease their power output by up to half*. These build-ups of dust are further compounded by settling pollen and agricultural clouds, borne from commercial ploughing and harvesting that starts this time of year.
Bird guano is another major disruptor of energy generation. Summer sees peak numbers of birds in the UK, due to a combination of migrants returning from Africa and resident eggs hatching over the past month. This influx means UK homes and businesses are at risk of significantly higher levels of bird guano building up on their solar panels, again reducing their capacity.
Manufacturers recommend panels be regularly cleaned to minimise the risk of dust, agricultural clouds and bird guano blocking or scattering incoming sunlight. Rentokil Specialist Hygiene provides an innovative, expert solution that is twice as fast as traditional techniques. Utilising pure deionised water to remove dirt and debris from solar panels, the organisation is able to boost Britain’s generation potential, without leaving lime deposits behind on the glass.
Jamie Woodhall, UK Technical and Innovations Manager at Rentokil Specialist Hygiene comments:
“One in six homes and businesses now have solar panels yet few of us realise just how much money we could be missing out on by failing to have them regularly cleaned. Manufacturers recommend panels are cleaned up to twice a year, and with hotter, drier springs and summers in the UK becoming more common, dust and pollen deposits are a growing problem.
“Failing to clean your solar panels could cut your generation capacity by the equivalent of eight hours in June, reducing output to the same levels as the depths of winter. Our advanced solar panel cleaning services remove dirt and debris from solar panels without damage or residue, helping them to maintain their maximum efficiency and prevent long-term performance decreases”.