What to look for in a solar panel installer
- MCS certification (mandatory for SEG payments) — The Microgeneration Certification Scheme (MCS) is essential. Without an MCS-certified installer, you cannot register for the Smart Export Guarantee (SEG), which pays you for electricity you export to the grid. MCS certification also ensures the installation meets industry standards.
- Roof structural assessment — Solar panels add weight to your roof — typically 15–20 kg per panel. A competent installer will assess whether your roof structure can support the additional load, particularly on older properties or lightweight roof constructions. They may involve a structural engineer for larger systems.
- Inverter vs microinverter choice — A string inverter converts DC from all panels into AC in a single unit — cheaper but less efficient if panels are partially shaded. Microinverters are fitted to each panel individually, offering better performance in shaded conditions but at higher cost. The installer should explain which suits your roof and why.
- Degradation warranty (25 years standard) — Quality solar panels come with a performance warranty guaranteeing at least 80–85% output after 25 years. Ask about the panel brand, the specific warranty terms, and who honours the warranty if the manufacturer exits the UK market. A product warranty of at least 12 years for the panels and 10 years for the inverter is standard.
- DNO G99 application knowledge — Any solar installation that exports to the grid requires notification to the Distribution Network Operator (DNO) under the G99 process. For systems up to 3.68 kW (single-phase), this is a notification. For larger systems, pre-approval is required. The installer must handle this application.
- Scaffolding responsibility — Solar panel installation requires scaffolding for safe roof access. The quote should clearly state whether scaffolding is included in the price, who erects it, and whether it complies with current health-and-safety requirements. Scaffolding costs can add £500–£1,500 to the total.
Questions to ask before hiring
- Are you MCS certified, and will I be able to register for the SEG? MCS certification is non-negotiable if you want SEG payments. Ask for the installer’s MCS registration number and verify it online. They should also help you register with an energy supplier for SEG payments after installation.
- Have you assessed my roof structure for the additional weight? This should be part of the initial survey. The installer should check the condition of roof timbers, the type of roof construction (trussed vs cut), and whether any reinforcement is needed. If they have not mentioned this, ask directly.
- Do you recommend a string inverter or microinverters for my roof? The answer depends on your roof layout, shading, and budget. If your roof has chimneys, dormers, or nearby trees that cast shadows, microinverters may perform significantly better. Ask the installer to justify their recommendation.
- What are the panel and inverter warranty terms? Expect a 25-year performance warranty on the panels and at least a 10-year warranty on the inverter. Ask who handles warranty claims — the installer or the manufacturer directly — and what happens if the installer is no longer trading.
- Will you handle the DNO G99 application and the SEG registration? Both processes require paperwork. A good installer handles the DNO application before installation and assists with SEG registration after commissioning. Ask how long each process takes and whether installation can proceed before DNO approval.
Red flags to watch for
- Not MCS certified. Without MCS certification, you cannot claim SEG payments and the installation may not meet industry standards. This is the single most important credential for a solar installer. Non-MCS installations also fail to qualify for certain green mortgage products.
- No roof structural assessment. Installing panels without checking the roof can cause structural damage. If the installer does not raise roof condition during the survey, they are skipping a critical step.
- Promises unrealistic energy savings. A reputable installer will provide generation estimates based on your roof orientation, pitch, shading, and system size — not vague promises. Ask for a SAP calculation or MCS yield estimate. If the savings figures sound too good, they probably are.
- Scaffolding not included in the quote. If the quote does not mention scaffolding, you may face an unexpected £500–£1,500 charge. Always confirm that scaffolding, access, and waste removal are included in the total price.
- Uses unbranded or grey-market panels. Quality panels from established manufacturers (JA Solar, Canadian Solar, Jinko, SunPower, Trina) come with verifiable warranties. Unbranded or grey-market panels may lack proper warranty support and could underperform or degrade faster.
Find rated solar panel installers in Kent
- Solar Panel Installers in Kent — county-level directory
- Solar Panel Installers in Maidstone
- Solar Panel Installers in Canterbury
- Solar Panel Installers in Dartford
- Solar Panel Installers in Tunbridge Wells
- Solar Panel Installers in Ashford
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