‘Heat Capacity’ is a physical approach to energy efficiency. This table full of pots and pans is a metaphor for the uneven way heat production and consumption are distributed across the city, and provides new views on how to make better use of the available overall capacity. Each item represents a different heat-producing principle. Drawing planners away from the drawing board, the system makes the now largely wasted energy felt and seen, leading to new perspectives and new solutions. The ultimate aim is to collect and interpret heat principles, to ensure a better control of heat flows and save energy and money.