Donnel Baird

America’s home-energy sector is a mess. About one-third of American households struggle to pay their energy bills, and nearly 30% of U.S. greenhouse gases come from heating, cooling, and operating buildings. Enter Donnel Baird, founder and CEO of BlocPower, a Brooklyn-based climate-­technology company that retrofits buildings in low-income neighborhoods with solar panels, electric heat pumps, and other green tech to lower energy bills and reduce planet-warming emissions. Baird knows what it means to be energy-impoverished; when he was a child, his family used to warm their home in the winter by leaving the stove burners on, and the oven running and open. His company is now partnering with Ithaca, N.Y., to decarbonize 1,600 buildings there; more than three dozen other cities have also expressed interest in working with him. Backed by crowdfunding and venture-capital firms, the company pays its investors back via savings on energy bills and selling back to the grid excess power generated by newly green buildings.

Write to Jeffrey Kluger at jeffrey.kluger@time.com.