Tier 1 Solar Panels: What the List Means and What It Does Not
Updated 23 October 2026 · SEO Dons Editorial
Who defines "Tier 1", and where is the list?
BloombergNEF (BNEF) says industry players often refer to "tier 1" suppliers but seldom define the term, and it publishes a methodology for its own list. The list itself is a paid product: only BNEF clients can access it, and BNEF warns that versions released on the internet may breach its licence terms and may have been doctored. This page therefore explains the method, from BNEF's methodology document of 4 September 2026, and does not reproduce the list.
Other "Tier 1" labels exist. One 2026 datasheet footer describes its maker as both a BNEF Tier 1 and an S&P Global Tier 1 manufacturer. This page covers BNEF's list because BNEF publishes how it works.
How does a manufacturer get on the list?
| Question | BNEF's published answer |
|---|---|
| What is measured? | Bankability: whether projects using the products have been offered non-recourse debt financing by banks |
| What is the bar? | Own-brand, own-manufacture products supplied to at least six different projects, financed non-recourse by six different commercial banks, in the past two years |
| How big must projects be? | Over 10 MW, from the 2Q 2025 list; the threshold was 5 MW before that, and 1.5 MW before 1Q 2024 |
| Who is eligible? | Makers that own production facilities and sell under their own brands; outsourced brands are not tiered |
| Where does the data come from? | Publicly disclosed project and financing information, mainly press releases and filings |
| How often does it change? | Quarterly, based on the previous two years; a company can drop off in any quarter, and only the latest list is valid |
| Are there other tiers? | No. BNEF keeps a Tier 1 list only and publishes no Tier 2 or 3 list |
BNEF explains the approach this way: banks and their technical advisers are typically unwilling to disclose their approved-product lists, so BNEF infers acceptance from deals that have closed. A maker that goes bankrupt, or defaults on major obligations, is removed.
What does Tier 1 not tell you?
BNEF is blunt about this. It says the classification is purely a measure of industry acceptance, does not directly account for product quality or financial strength, and that there are many documented examples of quality issues or bankruptcy among Tier 1 manufacturers. It adds that the list is not a recommendation and urges buyers not to use it as a measure of quality, but to consult a technical due diligence firm, which would usually look at the factory and bill of materials and probably run accelerated degradation tests on a sample.
The bar is also set by large financed projects, since only financings over 10 MW count. Nothing in the criteria is specific to a commercial roof or a particular model, and BNEF says it does not consider ESG performance.
Why can a Tier 1 brand sell a weaker product line, and a non-Tier 1 brand a sound one?
Because the test is about a company's financed projects, not each model. A listing is a record of recent bank-financed use, and module designs change faster than a two-year record. The IEA's 2025 failure-mode report notes that because of new methods for passivation layers, metallisation and thin glass, module reliability has to be re-optimised for each new manufacturing process. A maker can be listed while a newer line has thinner evidence behind it.
The reverse also follows from the published rules. A maker may be absent if it sells under a brand it does not manufacture, or has not had six qualifying bank-financed projects over 10 MW in two years, whatever the quality of its modules. Absence from the list is therefore not a finding of weakness. The brand comparison deals with named products.
What has changed recently?
BNEF dates its methodology changes, and they matter when you read a claim:
- 1Q 2024: the project-size threshold rose from 1.5 MW to 5 MW.
- 2Q 2025: it rose again to 10 MW. BNEF gives the growing size of the solar industry and the difficulty of verifying incoming project information as the reasons.
- March 2026: BNEF Tier 1 badges were launched, without changing the list methodology.
- September 2026: a web tool was launched on the BNEF client website that lets clients see which projects each equipment supplier has supplied.
A quarter-stamped badge belongs to the rules of that quarter, while an unlabelled claim from an earlier year may rest on a lower bar. Either way it measures financed use, not the module in your quote.
How do you check a Tier 1 claim?
BNEF says press releases and company claims are not evidence that a firm meets its criteria. Badges exist for listed firms that are BNEF clients, each timestamped with the relevant quarter, and BNEF says it cannot confirm Tier 1 status to non-clients. In practice a buyer should:
- Ask the supplier for the current, quarter-stamped badge, not a logo or a past press release.
- Treat an undated "Tier 1" line as unverified.
- Remember that a company can be removed in any quarter, so a badge is only good for its stated quarter.
- Allow for the rising bar: a claim from 2023 was made against a 1.5 MW project threshold, not today's 10 MW.
What should you check alongside it?
| Check | Why it matters |
|---|---|
| Certificates for the exact model | IEC 61215 and 61730 evidence, and MCS listing for systems up to 50 kWp; see the certifications guide |
| Who stands behind the warranty | BNEF notes bankruptcies among Tier 1 makers, so ask who handles UK claims and whether cover is insurance-backed; see the warranties guide |
| Degradation terms | First-year loss, annual loss and the output promised at year 25 or 30; see the commercial PV panels page |
| Bill of materials and factory | What BNEF says technical due diligence examines |
| Independent due diligence | BNEF's own suggestion for larger purchases |
A reader weighing quotes that lean on a Tier 1 label can send an enquiry through this site's form.
Sources
- BloombergNEF, Tier 1 Solar Module Methodology, 4 September 2026, checked 22 October 2026. The list itself is not public and is not reproduced.
- IEA PVPS Task 13, Degradation and Failure Modes in New Photovoltaic Cell and Module Technologies, February 2025, checked 22 October 2026.
- Canadian Solar, CS6.3-66TB datasheet v1.11, June 2026, cited only for how a maker describes itself, checked 22 October 2026.
Common questions
Is Tier 1 the same as high quality?
No. BNEF describes the classification as purely a measure of industry acceptance that does not directly account for product quality or financial strength, and notes many documented quality issues or bankruptcies among Tier 1 makers. Judge the specific model on certificates, test evidence and warranty terms.
Is there a Tier 2 or Tier 3 list?
Not from BNEF, which keeps a Tier 1 list only. Where a supplier talks about Tier 2 or Tier 3 panels, the label has no BNEF definition behind it, so ask what the supplier means and what evidence it rests on.
Where can I see the Tier 1 list?
Only BNEF clients can access it, and BNEF warns that versions circulating online may breach its licence terms and may have been doctored. Ask a supplier for the current badge with its quarter stamp instead.
How often does the list change?
Quarterly. BNEF usually publishes in the week after the 18th of February, May, August and November, and a company can be removed in any quarter. Only the most recent quarter's list is valid.