Do I need to clean my solar panels in the UK?

Rarely. UK rainfall handles routine cleaning. A professional clean every 3–5 years (£80–£150) is enough unless you're near trees, gulls or heavy traffic.

How long do solar panels last?

Modern Tier-1 panels are warrantied for 25 years at ≥85% of original output. Real-world data on early-2000s installs suggests 30+ years of useful life with a slow degradation curve (~0.4%/year).

What's the biggest maintenance cost?

Inverter replacement at year 10–12. Budget £900–£1,500 for a string inverter, more for hybrid/battery. Micro-inverter systems avoid this but cost more upfront.

Solar panel maintenance & cleaning (UK)

What you'll spend keeping a UK solar system running over 25 years — and the four things that actually need doing.

The short version

UK solar panels are essentially zero-maintenance. Over 25 years you'll typically replace one inverter (around year 12), clean the panels two or three times, and that's it. Total lifetime maintenance budget: £1,200 to £2,000 on a typical 4 kWp system.

Cleaning — less than you think

UK rainfall does most of the work. The MCS guidance is to clean panels every 3–5 years; in practice, urban homes near A-roads or under trees benefit from a clean every 2 years (£80–£150 by a roof-access company), rural homes can stretch to 5+ years. Bird droppings cause more output loss than dust — a localised wash with a soft brush and deionised water is enough.

Inverter — the one part that doesn't last 25 years

String inverters are warrantied 10–12 years, hybrid inverters typically 10 years (extendable to 20 with a paid extension at install). Expect to replace once during the system's life — 2026 replacement cost is £900–£1,500 for a typical 4 kWp string inverter, fitted. Hybrid and battery inverters cost more (£1,500–£2,500).

Micro-inverters and DC optimisers are warrantied 25 years and rarely need replacing — but they're more expensive upfront.

Monitoring & alerts

Every 2026 install ships with an app showing live and historical generation. Check it monthly; an unexplained 10%+ drop usually points to a tripped string, a failed bypass diode in one panel, or an inverter fault. Most installers fix faults under warranty in years 1–10.

Insurance & warranties

Panels are covered under standard buildings insurance — notify your insurer at install (it rarely changes the premium). MCS-certified installs come with: 2-year workmanship warranty (often extended to 10–25 years on premium installers), 10–25 year panel performance warranty, and DNO/MCS paperwork that's needed for resale.

Frequently asked questions

Do I need to clean my solar panels in the UK?: Rarely. UK rainfall handles routine cleaning. A professional clean every 3–5 years (£80–£150) is enough unless you're near trees, gulls or heavy traffic.
How long do solar panels last?: Modern Tier-1 panels are warrantied for 25 years at ≥85% of original output. Real-world data on early-2000s installs suggests 30+ years of useful life with a slow degradation curve (~0.4%/year).
What's the biggest maintenance cost?: Inverter replacement at year 10–12. Budget £900–£1,500 for a string inverter, more for hybrid/battery. Micro-inverter systems avoid this but cost more upfront.