TOPCon is the cell architecture that has replaced PERC as the mainstream choice in 2025 and 2026. The efficiency bump is real: a TOPCon panel hits 22 to 23 percent module efficiency versus 20 to 21 percent for PERC. That is roughly 10 percent more watts per square metre.
For a roof-constrained install, that matters. A 50 square metre rooftop in Accra that fits 8 kW of PERC will fit 8.8 kW of TOPCon. Over 25 years, that is real energy.
The heat performance is the bigger story. TOPCon panels have a lower temperature coefficient, around minus 0.30 percent per degree Celsius versus minus 0.35 to minus 0.40 for PERC. In Lagos in March, when cells run 20 degrees above ambient, that gap adds up to 1 percent of daily yield.
The price gap has narrowed. In early 2025, TOPCon cost 8 to 10 percent more than PERC. By mid-2026, the gap is closer to 3 to 5 percent. For most new projects, TOPCon is the default now.
When PERC still makes sense: large ground-mount projects where roof is not the constraint, and very cost-sensitive bids where every cent per watt counts. We still ship PERC for utility-scale tenders. For rooftop residential and commercial, TOPCon has won.