A solar system fitted between 2010 and 2015 is now between 11 and 16 years old. Most of it is still working, because there is very little to wear out, but the parts that do fail are predictable.
This article is about keeping an older system running and keeping its Feed-in Tariff income intact. It covers what usually goes wrong, what you can check yourself, and which repairs need somebody told about them.
Key Points
- The panels usually outlast everything else. Inverters, isolators, monitoring and roof fixings are what need attention.
- Your income depends on one number: the generation meter reading. If nobody reads it, nobody pays you.
- Ofgem does not allow estimated generation, so a dead meter means paused payments until it is sorted.
- Ofgem's supplier guidance says the eligibility period is 20 years for the majority of installations. So a 2011 system is roughly halfway through.
- The Energy Networks Association lists three ongoing duties for anyone with a connected generator. Keep it maintained by someone competent. Tell your network operator about incidents or failures. Tell them if you remove or replace a generating unit.
- Your FIT licensee should be told about modifications, and must be told if capacity changes or a meter is replaced.
- Systems from this period were connected under the older engineering recommendations, G83 or G59, not G98 or G99. That affects how replacement equipment is handled.
- FIT tariff rates are adjusted for inflation each year. Ofgem says the basis changed from RPI to CPI from FIT year 17, which runs from 2026 to 2027.
Common Misconceptions
- Solar is maintenance free. The panels need very little. The rest of the system does not.
- If the inverter light is on, everything is fine. An inverter can run while one string is dead. Compare the meter reading against previous years.
- My payments stopped, so my FIT has ended. More often a reading is missing, a meter has failed, or a licensee query is open. Check before assuming.
- Cleaning the panels will fix a big drop in output. Dirt causes small losses. A sudden large drop is usually a fault, not dirt.
- Nothing can be done because the original installer has gone. Any competent installer can work on the system. We repair systems fitted by other companies.
- Repairs will end my tariff. Ofgem says repairing or replacing generating equipment does not, in itself, affect the compliance of an accredited installation.
Real-World Advice
One Polegate customer's older solar had faults and he could not reach the original installers. We made his system safe, then upgraded the whole thing. If nobody will answer for your system, it is worth asking someone local.
A Hailsham customer came to us to replace an older system. They said the work was tailored to their needs, with real attention to detail.
Both jobs were on other companies' installations. Our published projects at our work page are all new 2026 installations, so neither of these has a case study page yet.
UK-Specific Considerations
Salt air and exposure. Systems along the East Sussex coast sit in a harsher environment than inland ones.
Rooftop DC isolators. Many systems from this period have an isolator switch mounted outside. These are a known weak point on older installations.
Older connection rules. Systems commissioned before 27 April 2019 were connected under G83 or G59. The Energy Networks Association guide covers replacing a generating unit installed under G59. Discuss with the network operator whether the new equipment stays under G59 or moves to G99. It also says you should tell the network operator if you replace interface protection.
Bird proofing and shading. Trees planted when the panels went in are much bigger now. One shaded panel can drag down a whole string on an older system without optimisers.
Monitoring that has quietly stopped. Old monitoring portals get switched off, routers change, and nobody notices for years. Without monitoring, the only evidence you have is the meter reading. That is another reason to keep photographing it.
Roof repairs are allowed. Ofgem says you may be able to remove an accredited installation from site temporarily, for example during roof repairs. This is reviewed case by case. It also says the site must not change, and that you cannot claim FIT payments while the works are taking place.
Selling the house. The tariff does not follow the panels automatically. Our guide on taking over a Feed-in Tariff when you buy a house covers the transfer.
What to check, and how often
| Check | How often | Why it matters |
|---|---|---|
| Generation meter reading, photographed | Every quarter | It is what you are paid on. Ofgem does not allow estimates |
| Reading compared with the same quarter last year | Every quarter | The cheapest way to spot a fault |
| Inverter display and error codes | Monthly | Catches string and inverter faults early |
| Visual check of the array from the ground | Twice a year | Slipped panels, bird nests, new shading, damaged cabling |
| Isolators, cabling and enclosures | At a service visit | Weather damage and corrosion, especially near the coast |
| Roof fixings and flashings | At a service visit | A leak found late is far more expensive |
| Monitoring still reporting | Yearly | Silent monitoring hides slow decline |
When This Isn't Right For You
- The roof needs replacing anyway. Then plan the roof and the solar together.
- The system is leased or on a rent a roof agreement. You may not own the equipment, so ask before commissioning any work.
- The array is unsafe to access without scaffolding and nobody has priced that in.
Before You Spend Money
- Get your FIT statement out and find your end date. Ofgem's supplier guidance says the eligibility period is 20 years for the majority of installations, and the end date is calculated for your specific installation.
- Compare this year's meter reading with previous years before calling anyone. It tells you whether you have a real fault.
- Ask for a diagnosis before a quote for replacement. A dead inverter and a tripped isolator look the same from indoors.
- Ask what the repair does to your accredited capacity. Same capacity keeps things simple. Higher capacity is an extension and earns nothing under FIT.
- Ask who notifies your FIT licensee and your network operator, and get copies.
- Weigh the remaining term. Money spent on a system with 5 years of tariff left needs a different sum from one with 12 years left.
Frequently Asked Questions
Q: How long does a Feed-in Tariff last?
A: Ofgem's supplier guidance says the eligibility period is 20 years for the majority of installations. Different arrangements apply to systems that transferred from the Renewables Obligation. Your end date is on your record with your licensee.
Q: My payments have stopped. Has my tariff ended?
A: Not necessarily. Missing readings, a failed generation meter or an open query all stop payments. Ofgem does not allow estimated generation, so a meter fault pauses payment until it is fixed.
Q: Will repairs affect my Feed-in Tariff?
A: Ofgem says repairing or replacing generating equipment does not, in itself, affect the compliance of an accredited installation. Tell your licensee about the change, especially if capacity or the meter changes.
Q: Can I have my roof redone with the panels on it?
A: The panels come off and go back on. Ofgem says temporary removal, for example during roof repairs, may be possible but is reviewed case by case. You cannot claim FIT payments while the system is not generating.
Q: My original installer has gone out of business. Who can help?
A: Any competent installer can work on the system. We repair and upgrade systems fitted by other companies, including ones where the original firm cannot be reached.
Summary
An older solar system usually needs attention rather than replacement. The panels are the durable part. The inverter, the isolators, the monitoring and the fixings are what age. Protect the income by reading and photographing the generation meter every quarter and by comparing it with last year. If something needs replacing, keep the capacity the same where you can. Tell your FIT licensee and your network operator. Remember that systems from this period were connected under older rules. That changes how replacement equipment is treated.