How to Choose a Solar Panel Installer – Why Installation Quality Matters

So before you choose who fits your system, here's what actually separates a good solar installer from a risky one.

1. MCS Certification Isn't Optional

The Microgeneration Certification Scheme (MCS) is the industry standard for solar and battery installations in the UK. It matters for three practical reasons:

It's required for government incentives. Without an MCS-certified installation, you won't qualify for the Smart Export Guarantee (SEG), which pays you for the electricity you export back to the grid.
It sets a minimum quality bar. MCS-certified installers are independently audited against defined technical standards — for the equipment used, the design of the system, and how it's installed.
It protects you if something goes wrong. MCS-certified work is covered by consumer protection schemes, giving you somewhere to turn if a dispute arises.

Always ask to see an installer's MCS certificate, and check it's current — certification has to be renewed and audited regularly, so an old or expired one is a red flag.

2. Proper System Design, Not a One-Size-Fits-All Quote

A good installer doesn't just count how many panels fit on your roof — they design a system around your home. That includes:

A site survey, not just satellite imagery. Roof pitch, orientation, shading from chimneys or trees, and structural condition all affect performance and should be assessed in person.
Correct panel layout and string design, so shading on one panel doesn't drag down the output of an entire row.
Right-sized inverters and batteries matched to your actual usage, not just the biggest system they can sell you.
Structural checks, especially on older roofs, to confirm they can safely carry the additional load.

If a quote arrives within minutes of a phone call with no survey, that's usually a sign of a sales process — not a design process.

3. Workmanship: The Part You Can't See From the Ground

This is where installation quality really shows. Common issues from poor workmanship include:

Roof penetrations that aren't properly sealed, leading to leaks months or years later
Cabling that isn't correctly routed or protected, creating fire risk or premature wear
Mounting systems installed with inadequate fixings for the roof type, risking panels coming loose in high winds
Poor cable management around inverters and consumer units, making future maintenance harder and less safe

Ask prospective installers about the mounting systems and flashing they use, how they weatherproof roof penetrations, and whether their installation teams are direct employees or subcontracted. Direct, experienced teams tend to be more accountable for the quality of their own work.

4. Warranties: Read the Fine Print

Solar warranties usually come in layers, and it's worth understanding each one:

Product warranty – covers manufacturing defects in the panels themselves (typically 12–25 years)
Performance warranty – guarantees a minimum output level over time (panels naturally degrade slightly each year)
Inverter warranty – often shorter than the panel warranty, since inverters are more likely to need replacement within the system's lifetime
Workmanship warranty – covers the installer's own work, separate from the equipment manufacturer's warranty

That last one is critical, and it's the one homeowners most often overlook. A brilliant panel warranty means nothing if the installer used cheap fixings or poor flashing and isn't around — or willing — to fix it. Ask exactly what's covered, for how long, and what happens if the installer goes out of business (some warranties are backed by insurance-backed guarantees for extra protection).

5. Aftercare: What Happens After the Van Leaves

A responsible installer doesn't disappear once your system is switched on. Look for:

Commissioning documentation and system handover, explaining how to monitor and get the most from your system
Ongoing monitoring support, so issues like underperformance or faults are picked up early
A clear point of contact for servicing, questions, or warranty claims
Maintenance guidance, even though solar panels require very little upkeep

Good aftercare is often the clearest sign of a company that plans to be around for the long haul — which matters, given your warranties depend on it.

Questions Worth Asking Any Installer
Can I see your current MCS certificate?
Will you carry out an in-person site survey before quoting?
Who will physically carry out the installation — your own team, or subcontractors?
What workmanship warranty do you offer, and is it insurance-backed?
Can I see examples of similar installations, and speak to previous customers?
Why Experience Matters

Every roof is different, and experience is what allows an installer to spot problems before they become expensive ones — a tricky junction between roof sections, an older tile type that needs a different fixing approach, or shading patterns that shift through the seasons. Installers who've completed a large number of installations across a wide range of property types have simply seen more of what can go right, and wrong.

At GE, our track record is built on that kind of experience — full MCS certification, in-house design and installation teams, and a customer base happy to share their experience with our workmanship and aftercare. If you'd like to see examples of our installations or hear directly from homeowners we've worked with, we're always happy to share both.

The Bottom Line

Choosing a solar installer isn't just about price or the panels on the spec sheet — it's about who's doing the work, how carefully, and what happens if something needs attention years down the line. Ask the right questions, check the certifications, and look past the sales pitch to the workmanship underneath it.

Thinking about solar for your home? Get in touch for a free, no-obligation site survey and see how our approach to quality installation compares.