What is HJT (Heterojunction)?
Heterojunction technology, a premium N-type cell combining crystalline and amorphous silicon for top efficiency.
Quick Answer
HJT panels are a premium choice in the UK, valued for low degradation and strong performance across the UK's varied conditions. They are less common than mainstream TOPCon but available through premium installers, notably via REC's Alpha Pure range. Expect to pay more per panel than for a standard TOPCon module.
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
HJT (Heterojunction) Explained
HJT (Heterojunction Technology, sometimes written HIT) combines a crystalline silicon core with ultra-thin layers of amorphous silicon on both surfaces. These layers passivate the cell, cutting electron losses to deliver around 22.5–24% efficiency, an excellent temperature coefficient (less output lost on hot days), and very low degradation of around 0.25% per year. HJT is a premium technology used by brands such as REC (Alpha Pure) and, historically, Panasonic. It competes with back-contact technologies like IBC, ABC and HPBC.
How Does HJT (Heterojunction) Work in the UK?
HJT panels are a premium choice in the UK, valued for low degradation and strong performance across the UK's varied conditions. They are less common than mainstream TOPCon but available through premium installers, notably via REC's Alpha Pure range. Expect to pay more per panel than for a standard TOPCon module.
Frequently Asked Questions
What does HJT stand for in solar panels?
HJT stands for Heterojunction Technology. It combines crystalline silicon with thin amorphous silicon layers to reduce energy losses, giving high efficiency (around 22.5–24%), an excellent temperature coefficient, and very low degradation.
Which brands make HJT solar panels?
REC is the best-known HJT brand in the UK, with its Alpha Pure range. Panasonic also used HJT (its HIT and EverVolt panels) before exiting the market, with REC having been its manufacturing partner. Several Chinese makers also produce HJT panels.
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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.