One of America’s largest rooftop-solar installation businesses filed for chapter 11 Monday, a stark illustration of the strains haunting the U.S. clean-energy sector as shifting federal policies shake investor confidence.

Sunnova Energy said on Sunday it had filed for Chapter 11 bankruptcy protection in the United States, as the residential solar panel installer buckled under the pressure of mounting debt and weakening demand.

Sunnova Energy, the struggling Houston-based residential solar company, has filed for bankruptcy, according to court and regulatory filings. The Chapter 11 bankruptcy filing comes days after Sunnova told the U.