Blog · Published 2026-05-12

Commercial solar insurance: what UK businesses need in 2026

UK commercial solar PV installations require insurance considerations across the project lifecycle — installation phase (builders' all-risks), operating phase (commercial property insurance with solar declaration), and ongoing risks (fire, theft, weather damage, performance guarantees). The 2026 insurance landscape has matured significantly but commercial operators must understand the considerations.

Insurance during installation

During the installation phase, your installer should hold:

- Public liability insurance: £5m+ minimum for systems under 250kWp; £10m+ for larger. - Employer's liability insurance: Statutory requirement, £10m+ standard. - Professional indemnity insurance: £1m+ for design errors. - Builders' all-risks insurance: Project-specific cover for site/materials damage during construction.

Verify these before signing the installer contract:

- Request certificate of insurance for each policy - Verify cover is in force on installation start date - Verify policy excess is reasonable (not punitive) - Verify the policy specifically covers solar installation work

Many commercial property owners now require their installer to add the property owner as 'additional insured' on the builders' all-risks policy — protecting the property during installation.

Operating-phase insurance: commercial property

After commissioning, the solar system is part of your commercial property. Insurance considerations:

Commercial property insurance: Notify your insurer before installation. Most UK commercial insurers (Allianz, Aviva, RSA, Zurich, AIG, Beazley) now have established solar PV declaration processes. Typical:

- Premium impact: £150-£800/year additional for typical commercial property (varies by sum insured and risk profile) - Sum insured uplift: Solar PV system value added to building reinstatement value - Excess increase: Some insurers apply higher excess to roof-mounted plant - Specific exclusions to check: Fire spread via solar wiring; lightning damage; theft of panels; vandalism

Report accurately. Failure to disclose solar installation invalidates cover.

Recommended commercial solar declaration checklist:

- System size (kWp) - Panel and inverter manufacturer/model - Installation date - MCS certificate (where applicable) - DNO connection agreement - Annual maintenance contract details - Battery storage details (where applicable)

Fire risk and solar PV

Solar PV fires are rare but not zero. UK statistics suggest ~1 fire per 50,000 system-years. Causes:

1. DC arcing: Loose DC connections create arc faults. Modern inverters with AFCI (Arc Fault Circuit Interrupter) reduce risk substantially. 2. Hot spots: Damaged panels can develop hot spots. Annual monitoring catches. 3. Battery thermal runaway: Lithium iron phosphate is safer than NMC but not zero risk. UL 9540A tested batteries reduce risk. 4. Bad workmanship: Poor connections, undersized cabling, missing isolation. MCS / engineering certification reduces.

Fire mitigations:

- AFCI in inverters (now standard on modern UK systems) - DC isolators within 3m of panel array - Roof-mounted system disconnect for emergency services - Fire-rated cable for DC runs - Battery storage in dedicated fire-rated enclosure - Regular thermal imaging during O&M visits - Insurance compliance with FM Global / DRA standards (for large industrial)

FM Global Class 7-25 for solar PV: Major industrial insurers require FM Global compliance for large commercial sites. Specifies fire breaks, cable management, emergency disconnects, training for emergency services.

Theft and vandalism

Solar panel theft is rare in UK commercial. Typical commercial sites have:

- Roof access controlled (no public roof access) - CCTV coverage of roof areas - Theft requires specialist tools to disconnect panels - Resale market is limited

Vandalism risk varies by site:

- Urban / publicly-accessible sites: moderate risk - Rural / fenced sites: low risk - Schools / public buildings: moderate (children climbing)

Mitigations:

- Anti-tamper mounting hardware - Tamper-evident panel labels - CCTV / motion detection - Site fencing where applicable - Insurance covers most events

Commercial property insurance typically covers theft of fixed solar panels. Confirm with insurer; some policies require minimum security measures.

Performance guarantees

Some installers offer performance guarantees — promising minimum kWh generation. Read carefully:

Genuine performance guarantee:

- Guarantees specific kWh per year - Reimburses shortfall (typically against grid import rate) - Covers years 1-5 typically; longer at premium - Independent monitoring used

Marketing-style 'performance guarantee':

- Conditional on perfect maintenance - Excludes weather variation, soiling, partial shading - Often references PR (performance ratio) rather than kWh - Limited financial value

Insurance-backed performance bonds:

- Third-party insurer underwrites the guarantee - Premium added to installation cost - Provides financial certainty if installer fails - Standard on large UK commercial installations

For most UK commercial operators, a 5-year performance guarantee with insurance backing is reasonable. Longer guarantees are usually marketing rather than real protection.

FAQs

FAQs on this topic

Will commercial solar increase my insurance premium?

Slightly. Typical UK commercial property insurer adds £150-£800/year for solar declaration. Material as a percentage but small as an absolute cost on a £100k+ project.

Do I need separate solar insurance?

Not typically. Solar is treated as part of commercial property insurance with declaration. Some specialist solar policies exist but rarely needed for standard installations.

What about battery storage insurance?

Battery storage has specific fire risk requirements. FM Global UL 9540A certified batteries comply with most commercial insurer requirements. Premium impact typically £300-£1,500 additional.

Is performance guarantee worth paying for?

Insurance-backed 5-year performance bonds are reasonable. Longer guarantees often have limited real protection. Read the small print carefully.