How Long Do Solar Panels Last? (And What Wears Out First)
Solar panels usually keep working for 30 years or more, losing a little output each year. Inverters and batteries wear out sooner. Here's what to expect from each part, what the warranties cover and how to keep a system running well.
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- Modern panels are guaranteed to keep about 88% to 92% of their output after 25 to 30 years, and usually keep working after that.
- A long-term study by the US National Renewable Energy Laboratory found panels lose a median of 0.5% of output a year. Newer N-type panels are guaranteed to lose less.
- The inverter and battery usually need replacing before the panels. The Energy Saving Trust puts battery life at around 10 to 12 years.
- Spark systems come with a 30-year workmanship guarantee, and our panels carry a 30-year performance warranty.
How Long Do the Panels Last?
Panels have no moving parts, so they rarely just stop. Instead, they slowly produce a little less each year.
Researchers at the US National Renewable Energy Laboratory reviewed nearly 2,000 measured degradation rates and found a median loss of 0.5% a year (Jordan and Kurtz, NREL). Most newer panels are guaranteed to do better. The Aiko panels we fit are guaranteed to lose no more than 1% in the first year and 0.35% a year after that:
| Year | Guaranteed output | For a system making 6,365 kWh in year one |
|---|---|---|
| 1 | 99% | about 6,360 kWh |
| 10 | 95.85% | about 6,160 kWh |
| 20 | 92.35% | about 5,940 kWh |
| 25 | 90.60% | about 5,820 kWh |
| 30 | 88.85% | about 5,710 kWh |
Guaranteed minimum from the Aiko Neostar 3S+54 datasheet (Aiko, January 2026). The kWh column scales the 6.7 kWp example in our payback guide and is illustrative. Real output also varies with the weather each year.
So a panel that is 30 years old is still guaranteed to produce almost nine-tenths of what it did when new. Panels often carry on well beyond their warranty period, just at a slightly lower output.
What Wears Out First
The rest of the system has shorter lives than the panels, and it's worth planning for that.
| Part | Typical life or warranty | What to know |
|---|---|---|
| Panels | 25 to 30 year performance warranties | Lose a little output each year |
| Inverter | Shorter than the panels | Most systems need one inverter replacement over the panels' life. Microinverters often carry longer warranties, such as Enphase's 25 years. |
| Battery | About 10 to 12 years (Energy Saving Trust) | Capacity fades slowly. The EcoFlow OCEAN 2 we fit has a 15-year manufacturer warranty. |
| Mounting and wiring | Life of the system | Covered by the installer's workmanship guarantee |
Battery life from the Energy Saving Trust (October 2026). Microinverter warranty from Enphase UK. Check the warranty documents for the exact products in your system.
Understanding Solar Warranties
A solar system usually comes with three separate warranties, and they cover different things.
- Product warranty from the panel maker: covers manufacturing defects. Typically 25 to 30 years on premium panels; your handover pack names the exact panel and its warranty.
- Performance warranty from the panel maker: guarantees the output figures in the table above, for 30 years.
- Workmanship guarantee from the installer: covers the installation itself. Spark's is 30 years. The first 10 years are insurance-backed through HIES, and years 11 to 30 are backed directly by Spark.
Inverters and batteries have their own manufacturer warranties, usually shorter. Keep your handover pack, which has every warranty document in it.
Keeping Your System Running Well
Solar panels need very little looking after.
- Watch the app. Your monitoring app shows what the system generates. A sudden drop that isn't explained by the weather is the main sign of a fault.
- Let the rain clean them. On a typical pitched roof, rain keeps panels clean enough. Don't climb onto the roof to clean them.
- Keep birds out. Pigeons nesting under panels can damage cables. We fit a bird barrier as standard.
- Check after storms. If you see damage or loose panels, contact your installer rather than going up yourself.
Your Questions, Answered.
How long do solar panels last in the UK?
Usually 30 years or more. Modern panels are guaranteed to keep about 88% to 92% of their output after 25 to 30 years, and they often carry on working after that at a slightly lower output.
How much efficiency do solar panels lose each year?
A large NREL study found a median loss of 0.5% a year. Newer N-type panels, such as the Aiko panels Spark fits, are guaranteed to lose no more than 1% in year one and 0.35% a year after that.
How long does a solar inverter last?
Inverters have shorter lives than panels, and most systems need one replacement over the panels' life. Check the warranty on your inverter; microinverters often have longer ones.
How long does a solar battery last?
The Energy Saving Trust puts it at around 10 to 12 years. The EcoFlow OCEAN 2 battery Spark fits has a 15-year manufacturer warranty.
Do solar panels need maintenance?
Very little. Keep an eye on your monitoring app, let the rain keep the panels clean, and contact your installer if output drops suddenly or you see damage.
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