Solar panel degradation rates: what to expect — UK
All solar panels degrade over time — it's unavoidable physics. The question isn't whether your panels are degrading, but whether they're degrading faster than expected. Published research shows median degradation rates of 0.5–0.8% per year, but real-world rates vary significantly by climate, panel quality, and installation conditions. This guide is tailored for UK solar owners, where maritime climate conditions and shorter daylight hours create different challenges.
Symptoms to watch for
Signs that this issue may be affecting your system
Natural panel degradation
CommonAll solar panels lose efficiency over time at roughly 0.5–0.8% per year. Accelerated in extreme heat or poorly manufactured panels.
What you can check yourself
Actions you can take today without professional help
Natural panel degradation
Compare current annual production to your system's first-year output. A decline beyond 1% per year may indicate accelerated degradation.
When to get a professional inspection
Signs you need professional help
Expected inspection costs
Drone thermal audit
Most comprehensive option
Handheld thermal scan
Best for smaller systems
Electrical inspection
Inverter and wiring only
Find inspection providers
Is your system affected?
Use our free Solar Loss Checker to get a personalised diagnosis with an action plan.
Based on conservative solar performance modelling and published degradation data
Updated April 2026 · Structured performance modelling
How we calculate →