Trina Solar Panels Review UK: Vertex S+ Specs & Warranty

Trina Solar is one of the world's largest solar panel makers, and its Vertex S+ is a panel many UK homeowners will see on an installer quote without recognising the name. Founded in 1997 and headquartered in Changzhou, China, Trina has been listed on the Shanghai Stock Exchange's STAR Market (688599) since June 2020, and reported cumulative module shipments of more than 292GW by the end of the second quarter of 2025. This review covers what Trina actually sells for UK roofs, how the Vertex S+ performs on paper, and one warranty detail that is easy to miss.

Is Trina Solar a Tier 1 manufacturer?

Trina says it is on BloombergNEF's Tier 1 module list (its 2025 year-in-review cites the Q1 2025 list). Tier 1 is a measure of bankability — how readily banks will finance projects using a maker's panels — not a direct measure of panel quality. Our Tier 1 vs Tier 2 guide explains the difference.

Reliability testing is a better quality signal. Kiwa PVEL's annual Module Reliability Scorecard lists Trina as a Top Performer for 12 consecutive years, including 2026, with Top Performer results in six tests: thermal cycling, mechanical stress, hail stress, potential induced degradation, LID/LETID and PAN performance. Trina's own press release for the 2025 scorecard specifically names the Vertex S+ 445W. Note that the scorecard tests sample models built to a specific bill of materials, so it supports the brand's general record rather than guaranteeing every panel that lands on your roof.

The Vertex S+ TSM-NEG9R.28 at a glance

The Vertex S+ is Trina's residential-format panel, and the NEG9R.28 is the N-type i-TOPCon dual-glass version most often quoted in the UK. Figures below are from Trina's 2024 datasheet for the 430–460W range, using the 450W rating:

• Power and efficiency: 450W at 22.5% module efficiency (the range tops out at 460W and 23.0%).
• Construction: 144 half-cut N-type TOPCon cells, 1.6mm front and back glass, black anodised aluminium frame.
• Size and weight: 1,762 × 1,134 × 30mm and 21.0kg, so roughly 2m² per panel.
• Heat behaviour: temperature coefficient of Pmax of −0.29%/°C and a NOCT of 43°C.
• Loads: 5,400Pa snow and 4,000Pa wind test loads; junction box rated IP68.

The −0.29%/°C figure matters on a summer roof: output falls a little less per degree of heat than older P-type panels typically do. See our temperature coefficient guide for what that means in practice. For the cell technology itself, read TOPCon vs PERC.

A small caution: the 2m² footprint is on the large side for a 450W panel, so on a tight roof, check the layout with your installer before assuming the wattage per panel translates to more total kWp. Our roof layout guide shows how to sanity-check it. As a rough guide, eight 450W panels make a 3.6kWp system.

Trina warranty: 15 years or 25?

This is the part to read carefully. Trina's Vertex S+ datasheet states "up to 25 years" product warranty and a 30-year power warranty. Trina's Global Limited Warranty document (revision Z, for products delivered from 1 March 2025) sets out the terms in full, and as we read it the TSM-NEG9R.28 sits in the group covered by a 15-year limited product warranty for material and workmanship defects. Some retailers and reviewers list 25 years and others 15 (FMB's Vertex S+ 505W review gives 15), so treat 25 as something to be confirmed in writing rather than assumed.

The power warranty is clearer. For this panel type Trina guarantees no more than 1% loss in year one and an average of no more than 0.4% per year thereafter, so at least 87.4% of nominal output at year 30. Other points from the warranty document:

• The United Kingdom is on Trina's list of countries where the global warranty applies.
• It is transferable to a new owner provided the panels stay installed in their original location, which helps if you later sell a house with solar panels.
• Claims go to Trina's European service centre (Trina Solar (Schweiz) AG in Switzerland) and need a purchase invoice, serial numbers of the affected panels and photographic evidence.

In practice, ask your installer which product warranty term applies to the exact model on your quote, and get it in writing.

UK pricing

Our product database lists the Vertex S+ 450W at about £69.68 per panel for the hardware alone, and FMB's review of the higher-output 505W model puts Trina panels at under £100 each, excluding installation. Those are per-panel benchmarks, not system prices: scaffolding, inverter, labour and any battery drive the total. Our solar panel cost guide covers full installed costs.

MCS and Smart Export Guarantee eligibility

To be paid under the Smart Export Guarantee your installation must be MCS-certified, and MCS certification applies to specific panel models. Before signing, ask your installer to confirm the exact Trina model on your quote is on the MCS product database. Our MCS certificate guide explains what to ask for.

How Trina compares

Against other big names, Trina is a mainstream, good-value choice rather than the premium end of the market. Back-contact panels such as those in our LONGi review reach higher efficiency, while JA Solar's DeepBlue range (see our JA Solar review) competes closely on price and warranty. For the wider field, see our manufacturers guide and the best solar panels in the UK.

Our verdict

Trina is a large, well-tested manufacturer, and the Vertex S+ NEG9R.28 is a solid, sensibly priced N-type panel for a typical UK roof: 22.5% efficiency, a good temperature coefficient, dual-glass build and a strong 30-year power guarantee. The two things to pin down are the product warranty length (15 years versus the datasheet's "up to 25") and MCS listing for your exact model. Get quotes from an MCS-certified installer, and compare panel warranties as carefully as panel prices.