"Twenty-five year warranty" appears on every solar quotation in Bangladesh. It is close to meaningless on its own, because it usually refers to only one of at least three separate warranties, and rarely the one that will matter to you.

The three warranties

Product warranty (modules). Covers manufacturing defects — delamination, junction box failure, frame corrosion. Typically 10 to 15 years, sometimes 25 on premium modules. This is the one that covers a panel that breaks.

Performance warranty (modules). Guarantees the module still produces a stated percentage of rated output at a given year — commonly around 80–90% at year 25, with a defined annual degradation rate. This is the "25 years" being advertised. It covers gradual decline, not failure.

Inverter warranty. Usually 5 to 10 years, extendable. This is the one most likely to be claimed, because the inverter is the component with the shortest expected life in the system.

A quotation that says "25-year warranty" without separating these is describing the performance warranty and letting you infer the rest.

The question that matters

When something fails in year seven, who do I call, and where are they?

A manufacturer's warranty is a contract with a company that may be on another continent, denominated in a process you have to initiate, document and ship against. It is not worthless — but it is not the same product as an installer-backed warranty with local service and local stock.

Ask specifically:

  • Is there a local service presence for this inverter brand in Bangladesh?
  • Do you hold replacement stock, or is every claim an import?
  • What is your target response time for a fault?
  • Who pays for labour on a warranty replacement — because the part being free does not mean the swap is free

That last one is a frequent gap. Many product warranties cover the component and explicitly exclude the labour and transport to fit it.

What voids a warranty

Common exclusions worth knowing before you sign:

  • Installation by an uncertified installer
  • Physical damage, including from wind events if the structure was under-specified
  • Water ingress traced to installation rather than manufacture
  • Modification or repair by a third party
  • Missing commissioning documentation and serial number records
  • Failure to perform documented periodic maintenance

That last one is quietly important. Some warranties require evidence of maintenance. If you cannot produce records, a claim can be refused. Keep the commissioning pack and log every service visit.

The paperwork to demand at handover

Insist on receiving, in writing:

  • Module and inverter serial numbers, recorded against your site
  • Original manufacturer warranty certificates
  • Commissioning report with test results
  • As-built single-line diagram
  • Structural certification
  • Net-metering approval documentation, if applicable
  • O&M schedule and contact route

If a vendor cannot hand you this pack on the day of handover, the warranty conversation is theoretical.

Degradation is normal, and it is slow

One reassurance to end on. Modern crystalline modules degrade at roughly 0.4–0.6% per year after a slightly larger first-year drop. That is a gentle curve. A well-installed array commissioned this year will still be producing the large majority of its rated output when the warranty expires.

The components that need attention across that period are the inverter, the mounting structure, and the cable terminations — which is precisely why the structure specification and the inverter warranty term deserve more of your attention than the headline number.

Every Solar Masters installation is handed over with a complete documentation pack and serial-number record. Ask us what is included.