Why Has My Solar Output Dropped? Common Solar Panel Faults & Repairs in Dorset

Solar panels are built to sit quietly on your roof and just work, so it’s easy to assume everything is fine, until the savings on your electricity bill start to shrink. If your system isn’t producing what it used to, you’re not alone. Across Poole, Bournemouth, Ferndown and the wider Dorset area, we’re regularly called out to solar setups that have quietly dropped in performance, sometimes by a surprising amount.

Here’s an honest, plain-English guide to what tends to go wrong, what you can safely check yourself, and when it’s time to bring in a NAPIT-registered electrician.

How to tell your solar panels aren’t performing

A gradual dip is normal over many years, but a noticeable drop usually points to a fault. Warning signs to watch for include:

• Your monitoring app or inverter display showing lower generation than the same period last year
• A red or flashing warning light on the inverter
• Electricity bills creeping back up despite no change in how you use power
• Part of the system appearing to produce nothing at all
• Error codes or a blank screen on the inverter

Comparing this summer’s output to previous summers is one of the quickest ways to spot a problem, since strong Dorset daylight should be your system’s best-performing time of year.

Common solar panel faults we see in Dorset homes

Inverter faults

The inverter is the hardest-working part of any solar system and usually the first thing to fail. Most inverters last around 10 to 15 years, so on older installations a fault here is common. Error codes, repeated shutdowns or a completely dark display often trace back to the inverter.

DC isolator and wiring issues

Rooftop and outdoor isolators take a battering from Dorset’s coastal weather. Water ingress, corrosion and failed connections can trip the system offline or stop it generating. These faults sit on the fixed wiring side of the installation and should only ever be investigated by a qualified electrician.

Dirt, shading and bird nesting

Grime, moss, lichen and bird mess all reduce output, and gulls nesting under panels is a genuinely common problem near the coast. If neglected, panels can operate at a fraction of their potential, which is why regular cleaning matters as much as repairs. Our guide on how often solar panels should be cleaned and serviced covers this in more detail.

Panel-level faults

Individual panels can develop micro-cracks, hotspots or delamination, often invisible from the ground. A thermal survey can pinpoint an underperforming panel without guesswork, so you only replace what actually needs replacing.

What you can safely check yourself

There are a few things any homeowner can look at without touching the electrics:

• Check your monitoring app to see whether the whole system or just part of it is affected
• Look at the inverter display and note any error code or warning light
• Confirm nothing new is shading the panels, such as a grown tree or a recently installed aerial

Please don’t go further than this. Solar systems carry high-voltage DC that behaves very differently to normal household electricity, and it stays live whenever there’s daylight. Never open the DC isolator, remove covers or touch the wiring. Fixed-wiring work should always be left to a qualified professional.

When to call an electrician

If the basic checks don’t explain the drop, or you see error codes, tripping or scorching, it’s time for a professional diagnosis. As a NAPIT-registered local firm, we can fault-find safely, test the panels and inverter, and put things right. Booking in solar panel repairs in Dorset early usually means a smaller, cheaper fix than leaving a struggling system to get worse.

It’s also worth remembering that solar issues sometimes reveal wider problems with a property’s wiring. If your home hasn’t been tested in a while, an EICR electrical safety check gives you a clear picture of everything, not just the panels.

If your solar system isn’t pulling its weight, get in touch and we’ll take a proper look. A well-maintained array across Poole, Bournemouth and the rest of Dorset can generate significantly more than a neglected one, and often the fix is simpler than you’d expect.