Energy efficiency codes set minimum requirements for the energy-efficient design and construction/renovation of new and existing buildings. [Source: Cochrane & Dunn (2010), Energy Codes 101: A Primer for Sustainability Policy Makers, Working Paper, Reservation Green Lab].
Zero Energy Buildings are buildings that do not use fossil fuels but only get all their required energy from solar energy and other renewable energy sources. [Source: IEA (Laustsen J.) (2008) Energy Efficiency Requirements in Building Codes, Energy Efficiency Policies for New Buildings.]