Inverting HVAC for energy efficient thermal comfort in populous emerging countries

Emerging countries predominantly rely on room-level air conditioning units (window ACs, space heaters, ceiling fans) for thermal comfort. These distributed units have manual, decentralized control leading to suboptimal energy usage for two reasons: excessive setpoints by individuals, and inability to interleave different conditioning units for maximal energy savings. We propose a novel inverted HVAC approach: cheaply retrofitting these distributed units with "on-off" control and providing centralized control augmented with room and environmental sensors. Our binary control approach exploits an understanding of device consumption characteristics at on/off and factors this into the control algorithms to minimize consumption. We implement this approach as Hawadaar in a prototype 180 ft2 room to evaluate its efficacy over a 7-month period experiencing both hot and cold climates. We collect enough evidence to plausibly scale this evaluation, demonstrating countrywide benefits: with just 20% market penetration, Hawadaar can save up to 6% of electricity per capita in residential and commercial sectors --- resulting in a substantial countrywide impact.