What is PERC?
Passivated Emitter and Rear Cell, an upgrade to standard cells that adds a rear reflective layer to boost efficiency.
Quick Answer
Many UK systems installed between roughly 2018 and 2023 use PERC cells. New installs are increasingly moving to N-type TOPCon and HJT, which offer higher efficiency and lower degradation. PERC panels remain a cost-effective, proven option and are still widely available through UK installers.
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
PERC Explained
PERC stands for Passivated Emitter and Rear Cell. It adds a passivation layer to the back of a standard monocrystalline cell, which reflects unabsorbed light back through the cell for a second chance to be captured and reduces electron recombination. This lifts efficiency by 1–2 percentage points over older cells, to roughly 20–22%. PERC was the dominant residential cell technology of the late 2010s and early 2020s, though it is now being overtaken by N-type technologies like TOPCon and HJT.
How Does PERC Work in the UK?
Many UK systems installed between roughly 2018 and 2023 use PERC cells. New installs are increasingly moving to N-type TOPCon and HJT, which offer higher efficiency and lower degradation. PERC panels remain a cost-effective, proven option and are still widely available through UK installers.
Frequently Asked Questions
What is the difference between PERC and TOPCon?
PERC is an older P-type technology at around 20–22% efficiency. TOPCon is a newer N-type technology that adds a thin oxide layer for around 22–23% efficiency, lower degradation, and better low-light performance. TOPCon is gradually replacing PERC as the mainstream choice.
Are PERC solar panels still good?
Yes. PERC panels are a proven, reliable technology and remain good value. They are slightly less efficient than the newer TOPCon and HJT cells, but for a roof with plenty of space they can still be a sensible, cost-effective choice.
Related Guides
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.