Three billion people rely on traditional stoves and solid fuels. These energy use patterns exacerbate the global climate crisis (via increased carbon emissions) and forest degradation/deforestation (via daily fuelwood collection), and expose billions to toxic air pollution generated by dirty fuels. Widespread adoption of improved cookstoves (which use cleaner fuels or burn solid fuels more efficiently) may ease this “triple burden,” but recent research casts doubt on their potential, given low and slow diffusion. We challenge this pessimism based on a multiyear, three-phase field study comprising diagnosis, design, and experimental testing involving 1,000 rural Indian households. We show that demand for these improved energy technologies is high when supply chains are robust, technologies match local needs, and income and liquidity constraints are relaxed.