The passive city aims to take the principles behind a passive building and scale it up the level of the city.  These concepts were first explored in the 1970s at the University of Southern California and has only been recently rediscovered. The passive city approach considers all the buildings in a neighbourhood to ensure there is no overshadowing, while assuring access to both active and passive solar systems. Passive city design and passive house/building design need to go hand-in-hand to achieve the maximum levels of energy efficiency.

Passive design lowers lifecycle costs which preserving resources and minimising GHG emissions. The solar envelope only protects neighbouring properties. Architects need to ensure that their designs fall within the envelope and adopt the same approach at the building scale.

Simon Ratcliffe looks at some of the basic principles behind city level passive design.