Energy payback: An attributional and environmentally focused approach to energy balance in net zero energy buildings

•The logic behind energy balance methods for nZEBs is studied.•Energy balance methods thus far presented for nZEBs follow an avoided burden approach.•An energy payback balance is proposed for nZEBs.•The energy payback method is argued to be environmentally focused.•The energy payback method is argued to better abide to certain nZEBs definitions.

Net zero energy buildings (nZEBs) are understood as grid-connected buildings which do not require net inputs of non-renewable energy over a defined period of their life cycle. Energy requirements of nZEBs have until now been assessed based on the impact buildings have on the existing energy system. This paper introduces a new approach to nZEB energy balance that takes into account the actual amount of energy nZEBs require.Energy balance methods previously proposed for nZEBs are illustrated in a new way and expressed in a series of equations based on a common terminology. Taking a different standpoint on the very logic that lies behind energy calculations; this article presents a new approach to energy balance in nZEBs. The paper highlights the important difference between preventing an increase in the demand for grid energy and ensuring that a building requires no net non-renewable energy. The authors argue that an energy payback approach constitute a more adequate way to tackle the environmental challenges nZEBs are meant to help solving, and to abide to a definition which stipulates that nZEBs should require no net non-renewable energy.