Choosing a solar installer is arguably more important than choosing your panels. A world-class panel fitted badly will underperform for two decades. A budget panel fitted by a skilled, accountable team will quietly earn you money. Here is how to make the right call.
Why Certification Matters More Than Price
The UK solar market has grown fast. With it has come a wave of new entrants — some excellent, some not. Certifications exist to give you an objective filter before you spend thousands of pounds.
MCS — The Non-Negotiable Starting Point
The Microgeneration Certification Scheme (MCS) is the UK industry's primary quality mark for small-scale renewable installations. MCS certification is mandatory if you want to:
- Export electricity under the Smart Export Guarantee (SEG)
- Access any government or utility incentive scheme
- Have your installation recognised by mortgage lenders and EPC assessors
Always verify an installer's MCS number directly on the MCS website. Rogue traders have been known to display expired or borrowed certification numbers.
→ Curious what solar would actually put back in your pocket? Run a free 60-second estimate.
RECC — Consumer Protection Layer
The Renewable Energy Consumer Code (RECC) sits on top of MCS. RECC members commit to pre-contractual transparency, fair sales practices, and access to an independent Alternative Dispute Resolution (ADR) service. If something goes wrong with a RECC member, you have a clear escalation path without needing to go to court.
NICEIC — Electrical Competence
Solar PV is a notifiable electrical installation. Your installer must be competent to sign off the AC wiring work. The NICEIC (National Inspection Council for Electrical Installation Contracting) is the UK's leading electrical certification body. An NICEIC-approved installer can self-certify the electrical work without requiring a separate building control inspection in most local authority areas.
IWA — Roof Integrity
The Institute of Waterproofing Assessors (IWA) accreditation signals that an installer has been trained in roof penetration and waterproofing best practice. Not every installer holds this, but for tiled roofs where penetrations are made, it is a meaningful differentiator.
How to Check Reviews Without Being Fooled
Verified review platforms are more reliable than testimonials on installer websites.
- Trustpilot — Look for volume (at least 50 reviews) and recency (within the last 12 months)
- Google Business Profile — Difficult to fake at scale; check for photo evidence of actual installations
- Which? Trusted Traders — Requires background checks and ongoing monitoring
- Checkatrade — Work is verified against the tradesperson's profile
Be cautious if an installer has a perfect score with only a handful of reviews, or if reviews appear in clusters (suggesting organised posting).
Comparison: Key Installer Credentials at a Glance
| Credential | Issuing Body | What It Guarantees | Required for SEG? |
|---|---|---|---|
| MCS | Microgeneration Certification Scheme | Installation quality & product standards | Yes |
| RECC | Renewable Energy Consumer Code | Sales conduct & consumer protection | No, but strongly advised |
| NICEIC | National Inspection Council (Electrical) | Electrical installation competence | Yes (or equivalent) |
| IWA | Institute of Waterproofing Assessors | Roof waterproofing standards | No, but valuable |
| Which? Trusted Trader | Which? | Pre-vetting and ongoing monitoring | No |
Red Flags to Watch For
- Unsolicited cold calls or door-to-door sales pitches
- Pressure to sign on the day with a "today only" discount
- Vague or absent product specifications in the quote
- No mention of scaffolding, DNO notification, or grid connection process
- Inability to provide verifiable MCS certificate numbers
- Payment terms requiring full payment upfront before installation
What a Good Quote Should Include
A credible quote from a UK solar installer in 2026 should specify:
- Panel brand, model, wattage, and efficiency rating
- Inverter brand and model (SolarEdge, Fronius, Sungrow, Enphase, SMA)
- Expected annual generation in kWh based on your postcode and roof angle
- Estimated SEG export earnings
- Scaffolding and roof survey costs (or confirmation they are included)
- DNO application details if your system exceeds 3.68 kW
- Workmanship warranty duration (look for a minimum of 10 years)