Solar Panel Maintenance & Cleaning

A genuine solar service is far more than a wipe-over. When a Lumos Energy engineer attends, we work through a fixed inspection routine built around MCS and NICEIC good practice, so nothing is missed and the visit leaves you with a documented record. Every job starts at the consumer unit and works outward to the roof.

The core checks on a residential service are:

• DC and AC isolators — we confirm both switch cleanly and that the DC isolator, often the first part to weather, is watertight and undamaged.
• Connections and MC4 plugs — loose or corroded connectors are the leading cause of arcing and hot joints, so we inspect for discolouration, moisture ingress and pull-tension.
• Mounting rails and clamps — after years of wind loading, clamp bolts can loosen; we re-check torque and rail integrity so panels stay secure.
• Earthing and bonding — continuity is verified to keep the array electrically safe.
• Inverter fault log — we download the full event history rather than glance at the display, catching intermittent grid or isolation faults.
• Generation check — actual output is compared against the expected yield for your array size and the season.
• Panel condition — a visual sweep for micro-cracks, delamination, hot spots and new shading.

Two things make this worth booking rather than ignoring. First, warranty upkeep: many panel and inverter manufacturers require evidence of periodic servicing before honouring a claim, so a logged annual check protects the guarantee you paid for. Second, small faults compound — a single underperforming string or a weeping connector quietly costs generation for months before it shows on a bill.

Because Lumos works across Wiltshire and a 30-mile radius, we service systems we fitted alongside those we didn't — the routine is identical whether it's a recent solar panel installation or a ten-year-old array. Someone booking a first service on an inherited system, for example after buying a house with solar panels in Chippenham, gets the same full inspection and a written summary of anything needing attention.

The inverter is the hardest-working component in your system and the one most likely to need replacing within the panels' lifetime. Panels routinely last 25 years or more, but a typical string inverter runs for around 10 to 15 years — some fail as early as eight, others push past 20. Heat is the enemy: an inverter in an unventilated loft or direct sun ages faster than one in a cool, shaded utility space.

Most string inverters carry a 10–12 year manufacturer warranty, sometimes extendable. Microinverters and power optimisers, such as Enphase or SolarEdge, are typically warranted for around 25 years, closer to the life of the panels. Knowing which type you have changes the maintenance conversation entirely.

When an inverter does fail, the repair-versus-replace decision turns on age, fault code and parts availability. As a 2026 guide, a like-for-like string inverter replacement on a 3–4kWp home costs roughly £700–£1,100 including labour; the unit alone is around £600–£1,200 with £200–£400 fitting. The faults we see most are isolation faults, grid-voltage trips and over-temperature shutdowns — the last often pointing at ventilation rather than the unit itself.

An ageing inverter is also an opportunity. Rather than swapping like-for-like, many homeowners upgrade to a hybrid, battery-ready inverter for around £1,400–£2,200, which lets storage be added later without a second inverter. If you're weighing that up, our guide to the best home batteries in the UK for 2026 compares the Sigenergy SigenStor, Tesla Powerwall 3 and GivEnergy All-in-One, and we can quote a retrofit battery for existing solar at the same visit. Adding battery storage to a re-inverter job spreads the scaffolding and labour across both.

Whatever route suits you, we log the inverter's fault history and serial at every service, so when replacement day comes there are no surprises — and homeowners with solar panels in Melksham or nearby get a same-radius call-out rather than a national-contractor wait.

Modern systems generate a stream of data, but most homeowners never look at it until a bill seems wrong. Part of a Lumos maintenance relationship is turning that data into an early-warning system. At the annual visit — and remotely in between — we compare your actual output against the expected yield, so a shortfall is caught in weeks rather than at year end.

The benchmarks matter. A well-sited 4kWp array in Wiltshire should produce roughly 3,900kWh a year, and panels degrade slowly — in the region of 0.5% per year, so a healthy 20-year-old array still delivers around 90% of its original output. If generation drops faster than that curve, something is wrong: a shaded or failing panel, a tripped string, or an inverter derating in the heat.

Where a system has per-string or per-optimiser monitoring, we can pinpoint a single failing panel rather than guessing, which keeps any repair targeted and cheap. We also set sensible alerts — zero-output and sustained underperformance — so the system tells you when it needs attention.

Two things we always verify. First, export metering: if you're on the Smart Export Guarantee, we confirm the meter is recording and that you're actually being paid for the surplus you send back — good SEG rates sit around 10.8p/kWh in 2026, so an unregistered or mis-reading meter is real money lost. Second, battery state-of-health: for homes with storage we check cycle count and usable capacity against the warranty curve, and confirm the system is still prioritising self-consumption over grid import at around 27p/kWh.

If the figures show a system generating well but still importing heavily in the evenings, that's usually a storage conversation rather than a fault — the fix is solar and battery working together, or diverting midday surplus into a car through EV charging from solar with a solar-divert charger such as a Zappi. Homeowners around solar panels in Devizes and the wider county get the same remote monitoring review as part of the plan.

British weather does some of the cleaning for you, but not all of it. Rain rinses loose dust, yet it does nothing for the lichen, moss, pollen film and bird fouling that build along panel edges and in the frame channels. That grime shades cells and creates hot spots, and real-world losses from a neglected array commonly run at 5–15%. For most Wiltshire homes a professional clean every 12 to 18 months — ideally in spring and again in autumn — keeps output where it should be.

How we clean matters as much as how often. Lumos uses pure, deionised water fed through a telescopic pole from the ground, so panels dry spot-free and nobody walks on the roof. That last point is important: standing on panels risks invisible micro-cracks that void warranties, and roof-walking is the single biggest safety hazard in the job. Professional cleaning typically runs about £4–£8 per panel, or £80–£150 for a standard domestic visit — a fraction of the generation it recovers.

Birds are the other recurring enemy. Pigeons love the warm, sheltered cavity beneath an array and will nest there; their droppings are corrosive and a hot-spot risk on the cells and wiring, and nesting debris blocks airflow and can chew into cabling. Bird-proofing — a mesh or clip system fitted around the array perimeter — typically costs £300–£900 for a residential roof. It is far cheaper fitted at installation, because retrofitting later usually means hiring scaffolding, so we flag it at the first service if your roof is exposed.

Cleaning and bird-proofing are the two jobs homeowners most often ask us to schedule together, and we set a cadence for your specific roof — panels under trees or near farmland need it more often. For the detail on timing, our guide on how often solar panels should be serviced breaks it down, and you can see how servicing sits alongside running costs on our solar panel costs in Wiltshire page. We cover Chippenham, Melksham, Devizes, Calne and the surrounding 30-mile radius.