Just how much do density and green space affect urban energy use? It depends on where you live.

Tree cover, paved surfaces, the spacing of buildings and green spaces all affect how much energy it takes to offset the ‘urban heat island effect.’ But the relative contribution of these urban form factors has been a matter of debate. Researchers seeking to clarify the matter presented a method for measuring the impact of each of these factors — and revealed that their contribution to building energy use varies between cities.