Three billion of the world’s poorest people mostly rely on solid biomass for cooking, with major consequences to health1 and environment2. We demonstrate the untapped potential of wireless sensors connected to the ‘internet of things’ to make clean energy solutions affordable for those at the bottom of the energy pyramid. This breakthrough approach is demonstrated by a 17-month field study with 4,038 households in India. Major findings include: self-reported data on cooking duration have little correlation with actual usage data from sensors; sensor data revealed that the distribution of high and low users varied over time, and the actual mitigation of climate pollution was only 25% of the projected mitigation; climate credits were shown to significantly incentivize the use of cleaner technologies.