Since the beginning of the 1990s buildings have been built all over the world which claim to achieve ‘zero energy’ or ‘plus energy’ standards. Often architects or developers have defined the principles (for example: higher energy efficiency, seasonal storage and renewable heat supply) according to which the buildings have been planned, as well as the relevant concepts for balancing energy consumption and energy generation. In due course, terms such as ‘energy autarkic house’, ‘zero thermal energy house’, ‘(net) zero energy building’ or ‘equilibrium building’, among others, have emerged.
The broad range of terms indicates the wide variety in approaches and makes orientation difficult. This article presents the most important zero energy standards and labels, analyses their differences and commonalities in terms of indicators and balance limits, and makes recommendations on how potentially to develop a common international understanding of what ‘zero energy’ is and what it isn’t.