There are various definitions of ‘zero energy’ and ‘net-zero’ energy building. In most cases, the definitions
refer only to the energy that is used in the operation of the building, ignoring the aspects of energy use
related to the construction and delivery of the building and its components. On the other hand the
concept of ‘net energy’ as used in the field of ecological economics, which does take into account the
energy used during the production process of a commodity, is widely applied in