--- title: "Tongwei TWMNH-66HD vs Tongwei TWMNH-66HS - Solar Panel Comparison | ComparePV" description: "Compare Tongwei TWMNH-66HD vs Tongwei TWMNH-66HS side by side: what actually differs, output when it is hot, thirty-year production, and the full specification." source: "https://comparepv.com/compare/tongwei-twmnh-66hd/tongwei-twmnh-66hs" updated: 2026-09-11 --- # Tongwei TWMNH-66HD vs Tongwei TWMNH-66HS Identical on every published parameter All 18 comparable parameters agree, with 1 more left out because at least one datasheet does not publish it. Two records this alike are usually one panel sold under two names, or two bins of the same production line - decide on price and on who you would rather buy from. ## The two panels | Attribute | A | B | | --- | --- | --- | | Panel | [Tongwei TWMNH-66HD](https://comparepv.com/panel/tongwei-twmnh-66hd) | [Tongwei TWMNH-66HS](https://comparepv.com/panel/tongwei-twmnh-66hs) | | Manufacturer | Tongwei | Tongwei | | Power | 620 Wp | 625 Wp | | Efficiency | 22.95 % | 23.14 % | | Technology | TOPCon | TOPCon | ## Every compared parameter | Parameter | 66HD | 66HS | | --- | --- | --- | | Rated power | 620 Wp | 625 Wp | | Module efficiency | 22.95 % | 23.14 % | | Power density | 229.5 Wp/m² | 231.4 Wp/m² | | Open-circuit voltage | 49.10 V | 49.25 V | | Voltage at max power | 40.82 V | 40.77 V | | Short-circuit current | 16.06 A | 16.14 A | | Current at max power | 15.19 A | 15.33 A | | Temperature coefficient | -0.280 %/°C | -0.280 %/°C | | Dimensions | 2382x1134x30 mm | 2382x1134x30 mm | | Module area | 2.701 m² | 2.701 m² | | Weight | 29.0 kg | 29.0 kg | | Weight per kWp | 46.8 kg/kWp | 46.4 kg/kWp | | Product warranty | 15 yrs | 15 yrs | | Performance warranty | 30 yrs | 30 yrs | | Annual degradation | - | - | | Cell technology | TOPCon | TOPCon | | Cell type | Monocrystalline | Monocrystalline | | Cell count | 132 | 132 | | Bifacial | Yes | Yes | ## Thirty-year yield A 1.0% first-year loss then 0.40% a year, assumed for both panels, at 1,200 kWh/kWp a year Same temp coeff. for both panels (-0.280 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other. - **Cumulative output, 66HD:** 20,802 kWh - **Cumulative output, 66HS:** 20,970 kWh - **Gap:** 168 kWh ## Output when hot | Condition | Cell temperature | 66HD | 66HS | Retained | | --- | --- | --- | --- | --- | | Standard test conditions | 25 °C | 620 W | 625 W | 100.0% of rated power | | Cool, bright day | 40 °C | 594 W | 599 W | 95.8% of rated power | | Typical summer roof | 55 °C | 568 W | 573 W | 91.6% of rated power | | Hot roof | 70 °C | 542 W | 546 W | 87.4% of rated power | ## Against the whole database | Measure | 66HD | 66HS | Out of | Note | | --- | --- | --- | --- | --- | | Efficiency | #2,268 | #1,509 | 14,005 | 66HS leads by 759 places | | Power density | #2,191 | #1,513 | 14,005 | 66HS leads by 678 places | | Heat behaviour | #1,309 | #1,309 | 14,005 | Tied - the same position in the database | | Weight | #1,343 | #1,141 | 14,005 | 66HS leads by 202 places | | Warranty | #21 | #21 | 14,005 | Tied - the same position in the database | | Overall | #2,013 | #1,789 | 14,005 | 66HS leads by 224 places | ## Questions ### Which panel is better: Tongwei TWMNH-66HD or Tongwei TWMNH-66HS? According to our database: **Tongwei TWMNH-66HS** has higher module efficiency (**23.14%** vs **22.95%**). See the full spec comparison and 30-year energy simulation above for a complete picture. ### What is the efficiency of Tongwei TWMNH-66HD and Tongwei TWMNH-66HS? **Tongwei TWMNH-66HD** has a module efficiency of **22.95%**, while **Tongwei TWMNH-66HS** is **23.14%**. Higher efficiency means more electricity from the same roof area - useful when space is limited. ### What cell technology does Tongwei TWMNH-66HD use vs Tongwei TWMNH-66HS? **Tongwei TWMNH-66HD** uses **TOPCon** cells; **Tongwei TWMNH-66HS** uses **TOPCon**. Modern **n-type** technologies (**TOPCon**, **HJT**, BC) typically deliver higher efficiency and lower degradation compared to older **PERC** (p-type) cells. ### What is the warranty on Tongwei TWMNH-66HD and Tongwei TWMNH-66HS? **Tongwei TWMNH-66HD** has a **30 years** power warranty; **Tongwei TWMNH-66HS** has a **30 years** power warranty. The power warranty guarantees a minimum percentage of rated output at the end of the warranty period (typically 80**-87%**). Product (materials) warranties are usually shorter. ### Are Tongwei TWMNH-66HD and Tongwei TWMNH-66HS bifacial panels? Both **Tongwei TWMNH-66HD** and **Tongwei TWMNH-66HS** are bifacial - they capture reflected light from the ground, which can add 5**-15%** more annual energy on ground-mount or elevated rooftop installations with a light surface beneath. ## Related comparisons - [Tongwei TWMNH-66HD vs Tongwei THC G12-66 Bifacial](https://comparepv.com/compare/tongwei-twmnh-66hd/tongwei-thc-g12-66-bifacial) - 11 differences, the largest is module efficiency - [Tongwei TWMNH-66HD vs Tongwei TWMNF-66HD](https://comparepv.com/compare/tongwei-twmnh-66hd/tongwei-twmnf-66hd) - 7 differences, the largest is rated power - [Tongwei TWMNH-66HD vs Tongwei TWMNH-54HD](https://comparepv.com/compare/tongwei-twmnh-66hd/tongwei-twmnh-54hd) - 6 differences, the largest is module efficiency - [Tongwei TWMNH-66HD vs Tongwei TWMNH-48HC](https://comparepv.com/compare/tongwei-twmnh-66hd/tongwei-twmnh-48hc) - 6 differences, the largest is module efficiency - [Tongwei TWMNH-66HD vs Tongwei TWMNF-66HD750](https://comparepv.com/compare/tongwei-twmnh-66hd/tongwei-solar-twmnf-66hd750) - 12 differences, the largest is module efficiency - [Tongwei TWMNH-66HD vs Tongwei TWMNF-66HD745](https://comparepv.com/compare/tongwei-twmnh-66hd/tongwei-solar-twmnf-66hd745) - 11 differences, the largest is module efficiency --- Source: https://comparepv.com/compare/tongwei-twmnh-66hd/tongwei-twmnh-66hs Not in this file, on the page: the thirty-year yield curve year by year at a cell temperature you pick and a written summary generated on request.