How long do solar panels last? (UK lifespan & degradation)

Solar panels typically last 25–30 years before output drops enough to matter, degrading gradually at around 0.5% a year rather than failing outright. The inverter is the part more likely to need attention, usually replaced once, around the 10–12 year mark. A battery, if you have one, has its own separate lifespan measured in cycles rather than years. None of this is a cliff edge; it's a slow, predictable decline you can plan around.

Panel lifespan: 25–30 years, with a guarantee to back it up

Most reputable panel manufacturers back their products with a product warranty (covering manufacturing defects, typically 10–15 years) and a separate, longer performance warranty (guaranteeing a minimum output level over time, typically 25 years, with some manufacturers now offering 30). These are two different promises:

• The product warranty covers the panel itself failing or being faulty.
• The performance warranty guarantees the panel will still produce at least a stated percentage of its original rated output by a given year, commonly 80–87% at 25 years, with some newer "linear" warranty structures guaranteeing a slightly higher figure.

Panels don't stop working when a warranty period ends: that's the manufacturer's guaranteed floor, not an expiry date. A panel installed today is very likely to still be generating usable electricity well past the 25-year mark, just at a somewhat reduced output compared with day one.

Degradation: a slow, steady decline, not a cliff edge

The industry-standard figure is roughly 0.5% output loss per year, sometimes quoted as a range of 0.3–0.6% depending on panel technology and manufacturer. Compounded over 25 years, that lands a typical panel at somewhere around 87–92% of its original output, broadly consistent with what performance warranties guarantee as a floor.

Most of that decline is invisible day to day. You won't notice a single year's 0.5% dip on your generation app; what you will notice, if you look at year-on-year totals over a decade or more, is a gradual downward drift that's entirely normal and already priced into every reputable savings estimate. It's also why an installer survey and a properly modelled savings estimate use degradation curves rather than assuming flat output for 25 years straight.

Inverter lifespan: the part that usually needs replacing

The inverter, which converts the DC electricity panels produce into the AC electricity your home uses, has a shorter working life than the panels themselves. Typical expectations:

• String inverters (the most common type for UK domestic systems) commonly last 10–15 years, with most manufacturer warranties in the 5–12 year range, sometimes extendable.
• Microinverters and power optimisers, fitted per-panel rather than as a single central unit, often carry longer warranties, sometimes matching the panel warranty, because failure of one unit only affects that panel rather than the whole array.

In practice, most UK homes with a 25-year-plus solar system will replace the inverter once during that lifetime, typically somewhere around year 10–12. Budgeting roughly £700–£1,200 for a like-for-like string inverter replacement (more, around £1,200–£2,000, for a hybrid inverter of the kind usually fitted alongside a battery, and less if it's still under warranty) is a sensible planning assumption rather than a guaranteed cost. See our guide to solar inverter types explained for more on how the different types compare.

Battery lifespan: measured differently, and separately from panels

If your system includes a home battery, its lifespan doesn't track the panels. It's governed by charge cycles as much as by years. Typical expectations:

• Most home batteries are warrantied for somewhere in the region of 4,000–6,000 cycles, or 10–15 years, whichever comes first.
• Like panels, batteries degrade gradually rather than failing outright: expect a battery to retain roughly 70–80% of its original usable capacity by the end of a typical warranty period.
• A battery cycled once a day (charge in the day, discharge overnight) will generally reach its cycle limit before it reaches its year limit, if it's on the higher end of daily use.

Because a battery is likely to age out before the panels do, it's the one component worth budgeting a mid-life replacement for. As a rough planning figure, a like-for-like home battery replacement runs somewhere around £3,000–£6,000 depending on size and brand, in the same spirit as the inverter figure above: a real cost to pencil in, not an exact quote. The reassuring trend is that batteries are increasingly outlasting their warranties, so this may land later than the cycle count alone suggests.

If you're weighing up battery size and expected lifespan together, our guide to what size solar battery do you need and the broader solar battery storage guide cover the sizing and value side in more depth. To see how the lifetime numbers land for your own roof, the savings calculator models generation, self-use and payback over the system's life.

What shortens a system's life

None of the above is guaranteed. A handful of factors can pull actual lifespan below the expected range:

• Poor installation: incorrect mounting, inadequate weatherproofing, or substandard cabling shortens life and increases fault risk. This is the strongest argument for using an MCS-certified installer rather than the cheapest quote.
• Physical damage: hail, falling debris, or extreme weather events can crack or degrade panels faster than normal wear.
• Moisture ingress and delamination: water getting into a panel's layers over time, more common in lower-quality or poorly sealed units.
• Consistently high operating temperatures: panels run hotter than ambient air, and sustained heat modestly accelerates degradation, though UK conditions are rarely extreme enough for this to be a major factor (more in our guide on solar panels in a heatwave).
• Neglect of visible faults: a cracked panel, a fault code on the inverter, or a sudden generation drop left unaddressed for years, rather than checked promptly.

Most of these are either designed out by using a reputable installer and decent-tier equipment, or caught early by keeping half an eye on your generation app.

End of life and recycling

When a solar system does eventually reach genuine end of life, decades from now for most installs, panels are covered under WEEE regulations (Waste Electrical and Electronic Equipment) in the UK, meaning manufacturers and distributors have obligations around take-back and recycling rather than panels simply going to landfill. A solar panel is largely recyclable: glass, aluminium framing, and a meaningful share of the internal materials (including silicon and some copper) can be recovered, with dedicated PV recycling infrastructure expanding across Europe as the first large wave of older installations starts to age out. For a system installed today, this is a distant consideration, but it's a reasonable one to have an honest answer to, rather than an unknown.

The practical takeaway

Budget for a system that outlives its own headline warranty: 25–30 years of panel life with a slow, well-understood decline, one inverter replacement somewhere in the middle, and a battery (if you have one) on its own separate cycle-based clock. None of that changes the near-term picture, namely what your roof can generate now and what that's worth on your bills, which is what an installer survey and a proper savings estimate actually tell you.

Frequently asked questions

Do solar panels stop working after 25 years?

No. Twenty-five years is typically the performance warranty period, guaranteeing a minimum output level (often 80–87% of original), not an expiry date. Panels generally keep generating well beyond that point, just at a somewhat reduced output compared with when they were new.

How much do solar panels degrade each year?

Around 0.5% of output per year is the industry-standard figure, sometimes quoted as a 0.3–0.6% range depending on the panel technology and manufacturer. Compounded over 25 years, that typically leaves a panel producing somewhere around 87–92% of its original output.

Do I need to replace my solar inverter?

Most likely, once, over the life of a 25-year-plus system, typically around the 10–12 year mark, though manufacturer warranties and inverter type affect the exact timing. Budgeting roughly £700–£1,200 for a like-for-like replacement is a sensible planning figure, though the real cost depends on warranty cover and the inverter type you have.

How long does a solar battery last compared to the panels?

A battery typically has a shorter, differently measured lifespan than the panels, commonly warrantied for around 4,000–6,000 charge cycles or 10–15 years, whichever comes first, with usable capacity gradually declining to roughly 70–80% of original by the end of that period. It's worth planning the battery and panel lifespans separately rather than assuming they match.

Related

• Solar inverter types explained
• MCS-certified installers explained
• What size solar battery do I need?
• Check if your roof is suitable for solar