1. Introduction
Buildings use a significant amount of energy for heating, ventilation, cooling, and lighting systems. Currently,
nearly 40% of the total primary energy in Norway is used in the buildings sector [1]. A strong interest in the
reduction of buildings’ energy consumption and the improvement of their environmental performance drives
researchers to look for new systems and technologies. Thus, the passive house, zero-energy building (ZEB), and netpositive-energy
building (NPEB) concepts have emerged and become increasingly attractive, particularly in Europe
and North America. In Europe, for example, the Energy Performance of Buildings Directives (EPBD) require that
all new buildings be ‘nearly zero-energy buildings’ by 2020 [2].