Solar Panel Maintenance 2026: Keep Your System Efficient

Solar panels need surprisingly little maintenance. Most systems run fine with an annual visual check and a clean every year or two. There's no annual service requirement like a boiler. But ignoring them completely can quietly cost you 10-25% of your energy output, so a small amount of attention goes a long way.

That's the short version. The longer version involves knowing what to actually look for, when to spend money on a professional, and when you can safely do nothing at all.

How Often Do Solar Panels Actually Need Maintenance?

Less than you'd expect.

Solar panels have no moving parts, no filters to replace, no fluids to top up. The panels themselves are tempered glass rated to survive hailstones, and the inverter (the box that converts DC to AC power) typically runs for 10 to 15 years before it needs replacing. Compare that to a gas boiler, which needs an annual service by law if you're a landlord, and you start to see why solar appeals to people who hate dealing with tradespeople.

The Energy Saving Trust recommends checking your system once a year and cleaning the panels when they're visibly dirty. That's it. No annual service contract required, no MOT-style inspection.

So what does "checking your system" actually mean? We'll get to the specifics in a moment, but the honest answer is that most of it involves looking at your generation data and glancing up at your roof. If the numbers look normal and nothing's obviously wrong, you're done.

One thing worth noting: the first year after installation is when problems are most likely to appear. Loose connections, incorrectly seated panels, inverter faults that only show up under real-world conditions. After that first year, most systems settle into a long, boring, productive life. Boring is exactly what you want.

What Does a Solar Panel Service Include?

Right, so let's say you do want a professional to look at your system. Maybe it's been a few years, maybe your generation numbers have dropped, maybe you just want confidence. Here's what a typical solar panel service covers:

Visual inspection. The engineer checks panels for cracks, chips, discolouration, and hot spots. They'll look at the mounting brackets, the roof tiles around the array, and the condition of the cabling.

Electrical testing. This is the bit you can't do yourself. They'll test the DC and AC output, check the inverter's performance against its rated capacity, and look for any earthing faults. A good engineer will compare your system's actual output to what it should be producing given its size and orientation.

Inverter check. Error codes, firmware updates, fan operation (if it has one). The inverter is the component most likely to fail during your system's lifetime, so this is where a service earns its money.

Generation data review. They'll look at your monitoring data (if you have it) for any unusual dips or patterns that suggest a panel or string isn't performing.

A professional service typically costs £100 to £200. Some installers offer it as part of a package when you buy the system, others charge separately. We see a lot of people paying around £150 for a combined clean and electrical check, which is reasonable.

Here's what most guides won't tell you: you don't necessarily need this every year. If your system is under five years old, your monitoring app shows consistent output, and you haven't had any storms or nearby building work, every two to three years is probably fine. The panels themselves are warrantied for 25 years. They're not fragile.

DIY Cleaning vs Professional Maintenance: Which Is Right for You?

£15 for a telescopic brush and a garden hose, or £150 for a professional with a van.

That's the basic choice, and honestly, for cleaning alone, most homeowners can handle it themselves. We've covered this topic in detail in our solar panel cleaning guide, but here's the quick version.

DIY cleaning works well if your panels are on a single-storey extension or a low-pitch roof where you can reach them safely from the ground with a long-handled soft brush. Use plain water. No detergent, no pressure washer, no abrasive pads. Rain does about 80% of the job naturally in the UK anyway, which is one of the few times our weather actually helps.

Don't go on the roof. Seriously.

Every year, people fall off roofs cleaning solar panels. The savings from a clean are real but modest, typically 3-5% improvement in output according to research from the University of California San Diego. That's maybe £20 to £40 a year on a typical 4kW system. It's not worth a broken leg.

Professional cleaning makes sense if your panels are on a high or steep roof, if you're near a main road (traffic film builds up faster than you'd think), if you're under trees that drop sap or bird mess, or if you simply don't want to bother. A professional clean costs £80 to £150 depending on your location and the size of your array.

But here's the thing about professional maintenance versus professional cleaning. Cleaning is cosmetic. Maintenance is electrical. You can clean your own panels, but you shouldn't test your own inverter or check DC string voltages unless you're qualified. The electrical side is where a professional actually adds value, because they can spot problems you'd never notice from the ground.

Warning Signs Your Solar Panels Need Attention

Your monitoring app is your best friend here.

If you've got a system with monitoring (and most systems installed in the last five years do), check your generation figures once a month. You're looking for sudden drops that don't match the weather. A cloudy week in November will obviously produce less than a sunny week in June, but if your July output is 30% lower than last July with similar weather, something's wrong.

Specific things to watch for:

A single panel producing noticeably less than the others. This shows up clearly on systems with microinverters or optimisers. It usually means a fault, shading from new growth, or physical damage.

Your inverter showing error codes or flashing red. Don't ignore this. Check your manual, and if the code doesn't clear after a restart, call your installer.

Visible damage after storms. Cracked glass, lifted panels, displaced mounting brackets. Check after any serious wind or hail event. Your home insurance should cover storm damage to solar panels, but you need to report it promptly.

Birds nesting under the panels. Pigeons love the gap between panels and roof tiles. It's warm, sheltered, and predator-free. The mess they create can block ventilation, attract vermin, and reduce output. Bird-proofing mesh costs £300 to £500 fitted, and it's worth it if you're in an area with pigeons. Ask anyone in central Manchester or parts of London.

Hot spots. These are areas of a panel that overheat due to cell damage or shading. You can't see them with the naked eye, but a thermal camera picks them up instantly. A professional service will check for these. Left untreated, hot spots reduce output and can eventually cause panel failure.

And one more that catches people out: tree growth. The tree that was fine when your panels went up five years ago might now be casting afternoon shade across half your array. Trees grow. Panels don't move. If your summer output has gradually declined year on year, look up before you call an engineer.

How Maintenance Affects Your Energy Output and Savings

10-25%. That's the range of output you could lose from a poorly maintained system.

At the lower end, you've got a bit of dirt and dust, costing you maybe 3-5% of potential generation. At the upper end, you've got a faulty panel, a degraded inverter, or heavy shading that's quietly eating your returns.

Let's put some numbers on it. A typical 4kW solar system in the UK generates around 3,400 to 4,200 kWh per year depending on location and orientation. At current electricity rates of roughly 24.5p per kWh (Ofgem price cap, Q2 2025), that's £833 to £1,029 worth of electricity.

Lose 15% of that to a fault you didn't spot, and you're throwing away £125 to £154 a year. Over five years, that's £625 to £770. Suddenly, a £150 service every couple of years looks like excellent value.

If you've got battery storage, the stakes are slightly higher, because any drop in generation means you're buying more from the grid to fill the battery, which defeats the purpose.

Honestly, this one depends on your situation and we can't give you a straight answer on exact savings. A well-oriented system in the south of England with no shading might barely notice skipping a clean. A partially shaded system in a city with heavy particulate pollution will see much bigger gains from regular maintenance. The monitoring data is your guide.

Can You Get Help With Solar Costs Through UK Grants in 2026?

So maintenance itself isn't covered by any grant scheme. No government programme will pay for your annual clean or inverter check. But if you're still thinking about getting solar panels in the first place, or upgrading an existing system, there is financial help available.

ECO4 can fully fund a solar panel installation for eligible households. You'll need to be on qualifying benefits like Universal Credit, Pension Credit, or Child Tax Credit, and your home typically needs an EPC rating of D or below. The scheme runs until December 2026. We've covered solar panel grants in detail separately, but the key thing for maintenance planning is this: if you get panels through ECO4, the installer's workmanship warranty should cover any faults in the first few years, so your maintenance costs are minimal initially.

The Warm Homes: Local Grant is the other one to know about. It's administered by local authorities and the funding varies by council, but some areas include solar PV as part of a whole-house energy efficiency package. Check the Warm Homes: Local Grant guide for current details.

And everyone benefits from 0% VAT on residential solar installations and maintenance. That's been in place since April 2022 and runs until at least March 2027. It applies to cleaning and servicing too, so if your professional service quote includes VAT at 20%, challenge it.

One tangent worth mentioning: the Great British Insulation Scheme closed in March 2026, so if you were hoping to pair insulation upgrades with solar maintenance, that particular route is gone. But ECO4 and Warm Homes: Local Grant can both fund insulation alongside solar if you qualify. Anyway.

The bottom line on maintenance costs is that they're small relative to what the system saves you. Budget £100 to £200 every two years for a professional check, keep an eye on your monitoring app monthly, and your panels should keep earning their keep for 25 years or more.

Open the eligibility checker. Two minutes. You'll see exactly which schemes you qualify for and whether solar, insulation, or both make sense for your home.