What is Solar Panel Efficiency?
The percentage of sunlight energy that a solar panel converts into electricity, typically 20–24% for modern panels.
Quick Answer
For UK installations, higher-efficiency panels (21–24%) are preferred because they generate more power per panel, which is important when roof space is limited. The most efficient panels available in the UK include SunPower Maxeon (24%), REC Alpha (22%), and Hyundai (22%). The efficiency difference between budget and premium panels is about 2–4 percentage points.
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
Solar Panel Efficiency Explained
Solar panel efficiency is the ratio of electrical power output to the solar energy hitting the panel surface. If a panel receives 1,000 W/m² of sunlight and produces 200W per square metre, its efficiency is 20%. Higher efficiency panels produce more power per square metre, meaning fewer panels are needed for the same system size. Efficiency has improved steadily from 15% in 2010 to 20–24% in modern residential panels.
How Does Solar Panel Efficiency Work in the UK?
For UK installations, higher-efficiency panels (21–24%) are preferred because they generate more power per panel, which is important when roof space is limited. The most efficient panels available in the UK include SunPower Maxeon (24%), REC Alpha (22%), and Hyundai (22%). The efficiency difference between budget and premium panels is about 2–4 percentage points.
Frequently Asked Questions
Does higher efficiency mean better value?
Not always. Higher-efficiency panels cost more per watt. If you have plenty of roof space, standard-efficiency panels may offer better value. Efficiency matters most when roof space is limited.
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John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He researches every battery and inverter brand against manufacturer datasheets, MCS and Ofgem data, and feedback from the MCS-certified installers in our directory before publishing.