Energy efficiency of strategies to enable temperature zoning during winter in highly-insulated residential buildings equipped with balanced mechanical ventilation

To reduce the space-heating needs, balanced mechanical ventilation equipped with a heat recovery is frequently implemented in highly-insulated residential buildings. This standard ventilation strategy tends to homogenize temperature inside the building, in other words, to reduce temperature zoning. In some countries, such as Norway, many users would like colder bedrooms. It has been proved that a significant part of the occupants in Norwegian passive houses opens bedroom windows during several hours every night during winter. Dynamic simulations have shown that it strongly increases the space-heating needs and that control only is unable to create temperature zoning in an energy-efficient way. The building concept should be changed. In the present contribution, the physical processes during temperature zoning are further explained. Detailed dynamic simulations of a detached single-family house are performed using the simulation software IDA ICE for different insulation levels, construction modes (which also influence the thermal insulation in partition walls) and control strategies. Alternative mechanical ventilation strategies are compared. They manage to reduce the influence of mechanical ventilation on the increased space-heating needs due to window opening but they cannot improve the large contribution of heat conduction through partition walls between heated areas and unheated bedrooms. Among the investigated ventilation strategies, decentralized ventilation has intrinsically the best performance