Canadian Solar vs Viessmann - solar panel manufacturer comparison
Canadian Solar has the broader catalog (292 vs 11 models). Canadian Solar leads on peak efficiency at 24.40%. Canadian Solar leans bifacial (46% of lineup).
Both catalogues are read from the manufacturers' own datasheets. A brand is not scored against the market here, only against the other brand on this page.
The two companies
Canadian Solar Inc. is a global renewable energy company founded in 2001. Headquartered in Kitchener, Ontario, it manufactures solar PV modules and provides battery energy storage solutions. The company also develops utility-scale solar power and battery energy storage projects.
- Founded
- 2001
- Headquarters
- Kitchener, Canada
- Annual capacity
- 51 GW/year
- Employees
- 17,113
- Listed
- NASDAQ: CSIQ
- Tier 1 bankable
- Yes
Catalogue against catalogue
An average over a catalogue describes the range a manufacturer publishes, not the module you would buy. A brand with two flagship panels and eighty older ones averages worse than one that has retired its back catalogue.
What each of them builds
Canadian Solar skews to higher efficiency: 13% of lineup is 23%+
Canadian Solar offers more 600W+ panels (24% of lineup)
Dominant cell tech: <strong>PERC</strong> (67%)
Dominant cell tech: <strong>PERC</strong> (73%)
The flagships
Written summary
Canadian Solar was founded in 2001 by Dr. Shawn Qu in Guelph, Ontario, and is listed on Nasdaq under CSIQ, with a newly expanded global headquarters in Kitchener, Ontario. The company holds Tier 1 status under BloombergNEF's bankability criteria, with surveyed banks, funds and EPC contractors unanimously rating its modules as bankable. Its manufacturing scale is substantial - module capacity stood at roughly 51 GW per year at the end of 2025, with some Tier 1 rankings citing up to 61 GW annual capacity, placing it among the largest module makers globally. Viessmann, by contrast, is a German company founded in 1917 with a long legacy in heating technology, now part of Carrier Global - it is not a cell or module manufacturer in the strict sense, instead sourcing its Vitovolt panels from Asian OEM factories built to its own specifications. On institutional footprint and raw production scale, Canadian Solar clearly has the stronger position.
Canadian Solar's portfolio spans residential modules, commercial and industrial (C&I) systems, utility-scale ground-mount projects, and battery energy storage, making it a flexible choice for installers and large-scale developers alike. Viessmann focuses mainly on the residential and small commercial segment through its Vitovolt 300 line, built on N-Type TOPCon cell technology in glass-glass construction, with efficiency reaching about 22.5 to 22.83 percent and warranties of 15 years product and 30 years performance. Viessmann's real strength lies less in chart-topping specs and more in system integration - pairing solar with heat pumps and home energy management under one brand.
For a typical buyer prioritizing bankability, production scale, and competitive pricing for large or budget-conscious installations, Canadian Solar is generally the stronger default choice. Viessmann suits buyers already invested in its heat pump or HVAC ecosystem who value single-brand integration, though independent tests note it carries a price premium of roughly 234 EUR/kWp versus a market average near 198 EUR/kWp, and efficiency that trails category leaders such as Aiko Solar, LONGi or Trina Solar.
Generated by Claude Sonnet 5 · 2026-10-02
Other brand comparisons
Shop prices: See 39 Canadian Solar offers · See 5 Viessmann offers
Comparisons are computed from manufacturer datasheets held in the ComparePV database and may not reflect a brand's complete current lineup. Nothing on this page is paid placement.