How long do solar panels and inverters last, and how fast do panels degrade?
Short answer
Panels typically last 25 years or more. Performance warranties usually promise 80–85% of rated power after 25–30 years; premium panels such as REC Alpha promise 92% at year 25. Inverters are the weak point. EST says expect to replace one after about 12 years, typically around about £800 (Energy Saving Trust; Checkatrade quotes £900) for a standard 4 kW unit.
Last checked 24 September 2026 · 4 sources
In more detail
- Product warranty (defects, often 5-15 yrs, some 25) is different from the performance warranty (output).
- Calculator default: 0.5%/yr degradation after year 1 (pending tier-1 datasheet check).
- EST: inverter warranties at least 5 years, often extendable to 15; a 15-year warranty may cost nearly as much as a replacement.
- NEA field study: in one landlord portfolio 90% of inverters had no failures after 9-10 years.
The facts, dated
- 01EST: panels last 25 years or more; inverter replace after ~12 years — 25+/12 years
market_data · UK · checked 24 September 2026 · Energy Saving Trust
- 02NEA: performance warranty 80-85% after 25-30 years — 80-85 %
market_data · UK · checked 24 September 2026 · nea.org.uk
- 03REC Alpha Pure-R/RX minimum power in year 25 — 92 %
manufacturer · n/a · checked 24 September 2026 · recgroup.com
- 04Checkatrade standard 4 kW inverter replacement — 900 GBP
market_data · UK · checked 24 September 2026 · checkatrade.com
What we saw in the field
[QA review 2026-09-24] I-9 AGREES: '80-85% output guaranteed after 25 years' matches NEA and older warranties; newer Tier-1 warranties are higher. I-6 UNVERIFIABLE: 'systems last ~30 years' is plausible for panels (EST 25+ years) but not inverters. Correction: EST puts inverter replacement at around £800 every 10-15 years; the £900 figure (for a 4 kW unit lasting ~12 years) is Checkatrade's, not EST's. C2-10 and C1-8 are product anecdotes, not tested.
Sources
- Energy Saving Trust — energysavingtrust.org.uk/advice/solar-panels/
- nea.org.uk — www.nea.org.uk/wp-content/uploads/2023/06/CP1495-Increasing-Self-Consumption-of-…
- recgroup.com — www.recgroup.com/en/warranty
- checkatrade.com — www.checkatrade.com/blog/cost-guides/cost-of-solar-panel-installation/
Last checked: 24 September 2026