Solar Carport Warranty — Full UK Coverage Terms

The Five Warranty Layers

1. Tier-1 panel performance warranty — 25 years

Every Tier-1 panel carries a 25-year linear performance warranty from the Tier-1 manufacturer (Trina Solar, Longi, JA Solar, JinkoSolar, REC, Canadian Solar). The warranty guarantees: 98% of nameplate output at year 1, 92% at year 12, and 84.8% at year 25. Glass-glass bifacial panels carry the strongest warranties; glass-back panels typically guarantee 90% at year 25.

Linear performance warranties are different from "product warranties". Product warranties cover manufacturing defects (typically 12-15 years). Performance warranties cover output degradation curves. Both apply concurrently. If a panel underperforms the linear curve, the manufacturer replaces or compensates.

2. Inverter warranty — 10 years (extendable to 25)

Leading commercial inverter brands (SMA Sunny Tripower, SolarEdge SE100K, Sungrow SG110CX, Huawei SUN2000) all ship with a 10-year standard manufacturer warranty. SMA and SolarEdge both offer warranty extensions to 25 years for ~5-10% of inverter cost — worth taking on projects where the carport is intended as a 25-year asset.

Why inverters fail before panels: they contain electronics with shorter design lives (~12-15 years). A single replacement at year 10-12 is normal lifecycle behaviour. Modern microinverters (Enphase) and optimisers (SolarEdge P-Series) carry 25-year warranties as standard.

3. Steel carport structure warranty — 25 years

Carport structures should be CE-marked, and the better suppliers offer a 25-year structural integrity warranty. The warranty covers: structural failure under specified wind/snow loading (Eurocode 1); galvanised zinc coating corrosion (BS EN 1461); powder coating durability (BS 3900); and steel certification (EN 10219:2006).

4. Workmanship warranty — 2 years standard, extendable to 10

Installation workmanship is typically covered by a 2-year standard workmanship warranty backed by the installer's public liability and professional indemnity insurance. Ask whether it can be extended to 10 years via an insurance-backed warranty. The extended warranty covers DC and AC cabling, mounting, weatherproofing, commissioning, and protection relay configuration.

5. Optional 25-year O&M performance guarantee

Some O&M contracts include a performance guarantee: if the carport generates less than an agreed share of forecast in a year (after weather adjustment), the provider credits the difference at an agreed kWh value. That turns a "buy and hope" warranty model into one where someone is accountable for the output.

What's covered vs not

Issue	Covered?	Why
Panel output below linear curve	✅	Tier-1 25-year performance warranty
Inverter electronics failure (years 1-10)	✅	Standard manufacturer warranty
Inverter failure (years 11-25)	If extended	Optional 25-year extension
Carport structure corrosion / failure	✅	25-year structural warranty
Cabling, mounting, weatherproofing defects	✅	2-yr standard / 10-yr extended workmanship
Storm damage (panels)	Insurance	Your commercial property insurance
Vandalism	Insurance	Your commercial property insurance
Theft (panels, copper)	Insurance	Your commercial property insurance
Lightning strike	Mixed	Surge protection covered; collateral damage = insurance
Vehicle impact on column	Your insurer	Commercial property + vehicle owner insurance
Underperformance from soiling / shading	If O&M	Cleaning and any performance guarantee under an O&M contract

How warranty claims work

If a panel or inverter fails, report it to your installer or O&M provider first; they normally manage the claim with the manufacturer:

1. Report the fault through your O&M contract or directly to the installer
2. The installer assesses the fault on site
3. If the panel or inverter warranty claim is valid, it is filed with the manufacturer
4. A replacement unit is shipped (Tier-1 manufacturers typically take 4-12 weeks)
5. The replacement is fitted, without a labour charge if your O&M contract covers it

Insurance you should also carry

A solar carport is plant + structure. Your commercial property insurer needs to add it to your policy — usually a small premium adjustment (0.1-0.2% of insured value per year). Provide your insurer with: the commissioning certificate, MCS certificate, structural drawings, and the replacement value (typically £950-£1,300/kWp).

Public liability — already covered under your commercial policy. Most insurers ask for evidence of vehicle column impact protection (specify impact-resistant kerbs or bollards at column bases).