Solar Carport Warranty: What Covers What
A solar carport is a long-life capital asset, and its warranty cover comes in layers from different parties: the panel and inverter manufacturers, the structure supplier and the installer. Solar Car Parks is an information site and provides no warranty itself. This page explains what each layer typically covers and what to ask for in writing.
The five warranty layers to look for
1. Panel product and performance warranties — typically 25 years
Panels from major (Tier-1) manufacturers such as Trina Solar, Longi, JA Solar, JinkoSolar, REC and Canadian Solar typically come with a 25-year linear performance warranty. A typical linear warranty guarantees roughly 98% of nameplate output at year 1, 92% at year 12, and 84.8% at year 25. Glass-glass bifacial panels often carry the strongest terms; glass-back panels typically guarantee about 90% at year 25. Check the exact terms in the datasheet and warranty document for the panel specified.
Linear performance warranties are different from "product warranties". Product warranties cover manufacturing defects (typically 12-15 years). Performance warranties cover output degradation curves. Both usually apply concurrently. If a panel underperforms the linear curve, the remedy (replacement or compensation) is set out in the warranty, so check the remedy and the claim procedure.
2. Inverter warranty — typically 10 years, extendable to 25
Leading commercial inverter brands such as SMA, SolarEdge, Sungrow and Huawei typically ship with a 10-year standard manufacturer warranty. Several manufacturers, SMA and SolarEdge among them, offer warranty extensions to 25 years for roughly 5-10% of inverter cost, which is worth pricing 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. Module-level electronics (microinverters such as Enphase, and optimisers such as SolarEdge P-Series) are commonly sold with warranties of up to 25 years.
3. Steel carport structure warranty — often up to 25 years
Carport structures should be CE-marked, and some suppliers offer a 25-year structural integrity warranty. Check what it 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). Also check who gives it, the structure manufacturer or the installer, and whether it still stands if the installer stops trading.
4. Workmanship warranty — typically 2 years standard, extendable to 10
Installation workmanship is typically covered by a standard workmanship warranty of around 2 years from the installer, which is only as good as the installer's ability to honour it. Ask whether it can be extended to 10 years via an insurance-backed warranty, and ask to see the installer's public liability and professional indemnity insurance. An extended warranty may cover DC and AC cabling, mounting, weatherproofing, commissioning and protection relay configuration; confirm the scope in writing.
5. Optional 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. Ask whether it is on offer and whether it is priced as a separate line item.
Who typically covers what
| Issue | Typically covered by | Notes |
|---|---|---|
| Panel output below linear curve | Panel manufacturer | Performance warranty (typically 25 years) |
| Inverter electronics failure (years 1-10) | Inverter manufacturer | Standard manufacturer warranty |
| Inverter failure (years 11-25) | Only if extended | Optional 25-year extension |
| Carport structure corrosion / failure | Structure supplier or installer | Structural warranty, if one is given: check its terms |
| Cabling, mounting, weatherproofing defects | Installer | Workmanship warranty (typically 2-yr standard / 10-yr extended) |
| 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 falls under product and workmanship cover; collateral damage is an insurance matter |
| Vehicle impact on column | Your insurer | Commercial property + vehicle owner insurance |
| Underperformance from soiling / shading | O&M provider, if contracted | Cleaning and any performance guarantee under an O&M contract |
How warranty claims work
If a panel or inverter fails, report it to the installer or O&M provider first; they normally manage the claim with the manufacturer:
- Report the fault through the O&M contract or directly to the installer
- The installer or O&M provider assesses the fault on site
- If the panel or inverter warranty claim is valid, it is filed with the manufacturer
- A replacement unit is shipped (Tier-1 manufacturers typically take 4-12 weeks)
- The replacement is fitted, without a labour charge if the O&M contract covers it
Warranty checklist: what to ask before signing
- Who gives each warranty (the manufacturer, the structure supplier or the installer), and in whose name is it issued?
- How long does each run, and what exactly is covered: parts, labour, removal and refitting?
- Is the workmanship warranty insurance-backed, and will it stand if the installer stops trading?
- Does the warranty transfer if the site or the business is sold?
- What is the claim procedure, and who pays for access equipment, labour and downtime?
- Are the warranty documents, datasheets and commissioning certificates handed over in writing at completion?
Insurance you should also carry
A solar carport is plant + structure. Your commercial property insurer will need to add it to the policy, usually as a small premium adjustment (often quoted at around 0.1-0.2% of insured value per year). Provide the insurer with: the commissioning certificate, the MCS certificate where one applies, structural drawings, and the replacement value (typically £950-£1,300/kWp).
Public liability is normally already part of a commercial policy; confirm this with the insurer. Insurers may ask for evidence of vehicle column impact protection (specify impact-resistant kerbs or bollards at column bases).
Questions about a warranty on your project
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