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SunPower introduces Monolith II panel with company-reported 522-watt output

SunPower says its REC-developed bifacial panel uses glass on both sides. Output and savings claims are vendor statements, not an independent home-performance test.

By Greener Numbers Editorial Team · Published October 8, 2026 · Updated 10/8/2026

SunPower announced Monolith II on October 8, 2026, describing it as a new residential solar panel developed through its joint development agreement with REC and exclusive to SunPower.

The company reports 522 watts of output from the same footprint and weight as its earlier 470-watt Monolith panel. Monolith II uses REC's N-Type heterojunction cell technology in a bifacial construction with glass on the front and back, according to the release.

Bifacial panels can collect light from both sides. The announcement describes front-side sunlight and reflected light reaching the rear. Actual installed energy production depends on conditions including mounting, shading and rear-side illumination. A panel's watt figure is not the same measure as a home's annual kilowatt-hour output.

SunPower says its first Monolith II installation is planned this month at a customer site where it intends to compare the two panels side by side. That is a planned test, not published independent field evidence.

The release contains claims about annual energy and customer value, but it does not establish a saving that every household will receive. This brief reports the product announcement and company-described design, not a verified claim that Monolith II is the most powerful panel on the market. It does not supply a retail price or promise a particular system payback.

Official source: globenewswire.com ↗