---
title: "JA Solar vs Viessmann - Brand Comparison | ComparePV"
description: "Compare JA Solar vs Viessmann solar panels: full portfolio, efficiency, cell technology breakdown, warranty terms and company background."
source: "https://comparepv.com/ja-solar-vs-viessmann"
---

# JA Solar vs Viessmann

JA Solar has the broader catalog (504 vs 11 models). JA Solar leads on peak efficiency at 24.80%. JA Solar leans bifacial (47% of lineup).


## The two companies


| Attribute | JA Solar | Viessmann |
| --- | --- | --- |
| Country | China | Germany |
| Headquarters | Beijing | Allendorf |
| Founded | 2005 | 1917 |
| Employees | 37,289 |  |
| Annual capacity | 100+ GW/year |  |
| Tier 1 | yes | no |
| Listed | SZSE: 002459 |  |
| Website | [https://www.jasolar.com](https://www.jasolar.com) | [https://www.viessmann.com](https://www.viessmann.com) |

JA Solar is a global leader in the manufacturing of high-performance photovoltaic products. Founded in 2005, the company designs, develops, manufactures, and sells solar cells and modules. JA Solar's products are used in ground-mounted power plants, commercial & industrial rooftop PV systems, and residential rooftop...


## Catalog & Power


| Measure | JA Solar | Viessmann | Margin |
| --- | --- | --- | --- |
| Panel Models | 504 | 11 | +493 |
| Max Power | 740 W | 405 W | +335 W |
| Avg Power | 456 W | 361 W | +95 W |


## Efficiency


| Measure | JA Solar | Viessmann | Margin |
| --- | --- | --- | --- |
| Max Efficiency | 24.80% | 21.30% | +3.50 pp |
| Avg Efficiency | 21.13% | 19.41% | +1.72 pp |


## Reliability & Warranty


| Measure | JA Solar | Viessmann | Margin |
| --- | --- | --- | --- |
| Avg Temp Coefficient | -0.322%/°C | -0.362%/°C | +0.040 |
| Bifacial Share | 238 (47%) | 0 (0%) | +47 pp |
| Avg Warranty | 27.9 yrs | 25.0 yrs | +2.9 yr |


## Efficiency distribution

JA Solar skews to higher efficiency: 15% of lineup is 23%+


| Efficiency band | JA Solar | Viessmann |
| --- | --- | --- |
| \<20% | 112 (22.2%) | 3 (27.3%) |
| 20-21% | 99 (19.6%) | 6 (54.5%) |
| 21-22% | 112 (22.2%) | 2 (18.2%) |
| 22-23% | 107 (21.2%) | 0 |
| 23%+ | 74 (14.7%) | 0 |


## Power distribution

JA Solar offers more 600W+ panels (14% of lineup)


| Power band | JA Solar | Viessmann |
| --- | --- | --- |
| \<400W | 142 (28.2%) | 6 (54.5%) |
| 400-499W | 173 (34.3%) | 5 (45.5%) |
| 500-599W | 120 (23.8%) | 0 |
| 600-699W | 60 (11.9%) | 0 |
| 700W+ | 9 (1.8%) | 0 |


## Cell technology

Dominant cell tech: **PERC** (49%)

Dominant cell tech: **PERC** (73%)


| Technology | JA Solar | Viessmann |
| --- | --- | --- |
| PERC | 247 (49.0%) | 8 (72.7%) |
| TOPCon | 146 (29.0%) | 0 |
| N-type | 90 (17.9%) | 0 |
| Unknown | 16 (3.2%) | 3 (27.3%) |
| HJT | 5 (1.0%) | 0 |


## Top panels, JA Solar


| # | Model | Power | Efficiency | Temp. coefficient | Technology |
| --- | --- | --- | --- | --- | --- |
| 1 | [JAM66D46-740/LB](https://comparepv.com/panel/ja-solar-jam66d46-740-lb) | 740 | 23.8 | -0.290 | Monocrystalline |
| 2 | [JAM66D46-735/LB](https://comparepv.com/panel/ja-solar-jam66d46-735-lb) | 735 | 23.7 | -0.290 | Monocrystalline |
| 3 | [JAM66D46-730/LB](https://comparepv.com/panel/ja-solar-jam66d46-730-lb) | 730 | 23.5 | -0.290 | Monocrystalline |
| 4 | [JAM66D46-725/LB](https://comparepv.com/panel/ja-solar-jam66d46-725-lb) | 725 | 23.3 | -0.290 | Monocrystalline |
| 5 | [JAM66D46-720/LB](https://comparepv.com/panel/ja-solar-jam66d46-720-lb) | 720 | 23.2 | -0.290 | Monocrystalline |
| 6 | [JAM66D46-715/LB](https://comparepv.com/panel/ja-solar-jam66d46-715-lb) | 715 | 23.0 | -0.290 | Monocrystalline |
| 7 | [JAM66D46-710/LB](https://comparepv.com/panel/ja-solar-jam66d46-710-lb) | 710 | 22.9 | -0.290 | Monocrystalline |
| 8 | [JAM66D46-705/LB](https://comparepv.com/panel/ja-solar-jam66d46-705-lb) | 705 | 22.7 | -0.290 | Monocrystalline |
| 9 | [JAM66D46-700/LB](https://comparepv.com/panel/ja-solar-jam66d46-700-lb) | 700 | 22.5 | -0.290 | Monocrystalline |
| 10 | [JAM66D46-695/LB](https://comparepv.com/panel/ja-solar-jam66d46-695-lb) | 695 | 22.4 | -0.290 | Monocrystalline |


## Top panels, Viessmann


| # | Model | Power | Efficiency | Temp. coefficient | Technology |
| --- | --- | --- | --- | --- | --- |
| 1 | [M405WE](https://comparepv.com/panel/viessmann-m405we) | 405 | 20.7 | -0.340 | Monocrystalline |
| 2 | [M405WK](https://comparepv.com/panel/viessmann-m405wk) | 405 | 20.7 | -0.340 | Monocrystalline |
| 3 | [M400WG](https://comparepv.com/panel/viessmann-m400wg) | 400 | 21.3 | -0.340 | Monocrystalline |
| 4 | [M400WE](https://comparepv.com/panel/viessmann-m400we) | 400 | 20.4 | -0.340 | Monocrystalline |
| 5 | [M400WK](https://comparepv.com/panel/viessmann-m400wk) | 400 | 20.4 | -0.340 | Monocrystalline |
| 6 | [M395WG](https://comparepv.com/panel/viessmann-m395wg) | 395 | 21.1 | -0.340 | Monocrystalline |
| 7 | [M395WK](https://comparepv.com/panel/viessmann-m395wk) | 395 | 20.1 | -0.340 | Monocrystalline |
| 8 | [M390WG](https://comparepv.com/panel/viessmann-m390wg) | 390 | 20.8 | -0.340 | Monocrystalline |
| 9 | [P265PGHC](https://comparepv.com/panel/viessmann-p265pghc) | 265 | 16.3 | -0.420 | Polycrystalline |
| 10 | [P260PGHC](https://comparepv.com/panel/viessmann-p260pghc) | 260 | 16.0 | -0.420 | Polycrystalline |


## Summary

JA Solar and Viessmann represent fundamentally different types of companies. JA Solar was founded in 2005 in China and is listed on the Shenzhen Stock Exchange; today it ranks among the world's largest dedicated solar PV manufacturers, with a production capacity exceeding 100 GW and a workforce of more than 37,000 employees. It holds Tier 1 bankable status, reflecting consistent recognition from major project finance institutions and independent testing bodies such as PVEL, where it earned a Top Performer designation for the tenth consecutive time in 2025. Viessmann is a century-old German energy systems group founded in 1917, primarily associated with heating systems, heat pumps, and HVAC solutions. Photovoltaics are a secondary product line for Viessmann rather than a core business, and the company does not hold Tier 1 bankable status; its current PV catalog comprises just 3 panel models with no disclosed annual production capacity in gigawatts.

The technical gap between the two portfolios is substantial. JA Solar's 524-panel range spans power outputs up to 740 Wp, with a maximum efficiency of 24.4% and an average portfolio efficiency of approximately 20.9%. Its most prevalent cell technology is PERC, covering over 52% of the lineup, with newer DeepBlue series models adopting TOPCon cells for higher output. Around 44% of JA Solar panels are bifacial, making them well-suited to utility-scale ground-mount projects and flat-roof commercial installations where albedo gain is available. The average product warranty across the portfolio extends to nearly 28 years, and a temperature coefficient of -0.32%/°C ensures solid performance in high-heat conditions. Viessmann's Vitovolt panels reach a maximum of 265 Wp and 16.3% efficiency, with no bifacial options in the current dataset and a less favorable temperature coefficient of -0.42%/°C. Viessmann's offering is best positioned for residential rooftop installs where customers are already invested in the broader Viessmann brand ecosystem and value the convenience of integrated heating and energy management from a single supplier.

For most international buyers - whether procuring panels for residential rooftop installs, commercial C&I projects, or utility-scale ground-mount farms - JA Solar presents a clearly stronger technical and commercial proposition: higher efficiency, broader product selection, bifacial options, Tier 1 bankable status, and a longer average warranty at competitive pricing. Viessmann is a reasonable consideration only where brand integration with an existing Viessmann heating or heat pump system is the overriding criterion and where the limited power and efficiency ceiling of the Vitovolt range is acceptable for the application. For standalone PV procurement evaluated on purely technical and financial merit, the advantage lies firmly with JA Solar.

Written by claude-sonnet from the figures above.


## Other comparisons

- [JA Solar vs A.B. Energy](https://comparepv.com/ja-solar-vs-a-b-energy)
- [AE Solar vs Viessmann](https://comparepv.com/ae-solar-vs-viessmann)
- [JA Solar vs AEET](https://comparepv.com/ja-solar-vs-aeet)
- [AIKO vs Viessmann](https://comparepv.com/aiko-vs-viessmann)
- [JA Solar vs AKCOME](https://comparepv.com/ja-solar-vs-akcome)
- [ARTsolar vs Viessmann](https://comparepv.com/artsolar-vs-viessmann)


---

Source: https://comparepv.com/ja-solar-vs-viessmann

Not in this file, on the page: the distributions above drawn as charts.