Heating, ventilation and air conditioning accounts for roughly 40–60% of a building’s energy use, yet the reason to run it at all is the comfort of the people inside. Pervasive and mobile computing makes it possible to sense individual thermal sensations and manage HVAC around them, but evaluating such systems is hard: real-world experiments are expensive, slow, privacy-sensitive and rarely cover the diversity of occupants and climates, while simulations have to be shown to reflect reality.