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How long solar panels last, and how much they fade
A worry that arrives with age: is the system quietly wearing out, and is it worth keeping? The honest answer is that panels fade slowly, and the part that fails is not the panels.
Panels fade slowly
Solar panels lose a little output each year, and the rate is small. Manufacturers commonly guarantee at least around 85 per cent of the original output after 25 years and quote figures as low as 0.3 per cent a year; independent studies of real systems put it at roughly 0.36 to 0.64 per cent a year. Either way, a panel a decade old is producing close to what it did when new.
Panels usually carry a 25 year performance warranty and a shorter product warranty of five to ten years. They do not stop at 25 years; they carry on generating at a gently declining output.
The inverter is what fails first
Not the panels, the inverter. It is the part that typically needs replacing after around 12 years, which is why many systems in the scheme have already had one changed. Crucially, that is a repair to an accredited installation, not a change to it, so it does not affect your rate. See replacing an inverter or a failed panel.
475,883 installations on the register were commissioned in 2013 or earlier, so they are into the years where an inverter change is normal and a panel or two may have been replaced. That is maintenance, not decline, and it does not forfeit an old high tariff.
What it means for your tariff
Your generation payment is paid per unit produced, so as a system fades a little each year it produces, and is paid on, slightly less. Over a couple of decades that adds up to a modest reduction, but it is small beside the thing that really changes the numbers, which is the end of your term, when both payments stop altogether. See what happens when your feed-in tariff ends.
Because the panels will still be generating long after the tariff ends, the value of the system in its later years is increasingly about the electricity you use yourself rather than the payments, which is the subject of getting the most from your system.
We hold the scheme data, not the performance of your particular panels. Degradation figures here are typical industry and study figures, not a measurement of your system; your own output is what your generation meter records over time.
Degradation and lifespan figures are typical industry and independent-study figures as summarised by the Energy Saving Trust. Installation counts by year are from the Ofgem Feed-in Tariff installation report of 2025-12-31. Information only, and not technical or financial advice.