Ever since the first "energy crisis" in the 1970s, the idea of low energy building has been addressed. A substantial amount of research work has been invested in North America and Europe to develop practical solutions. Theories have been tested in model buildings and the evolvement of results has been largely based on the method of trial and error.

Today the definition of low energy building can be differentiated into two specific approaches: the concept of 50 % and the concept of 0 %. The percentage numbers indicate the amount of energy these buildings use in comparison with the standard building constructed in accordance with current building regulations.