Optimising life cycle energy performance of housing: The value of occupancy control

There is a trend towards reducing heating and cooling requirements of buildings by using high levels of insulation, minimizing thermal bridging, and ensuring excellent air tightness, together with the operation of efficient mechanical ventilation heat recovery (MVHR) systems. In temperate climates, this approach has already raised questions about potential risks of over-specifying some construction elements and installations. This study argues that in maritime climates, appropriate building design with occupant controlled natural ventilation could provide an optimum life cycle energy performance. A heating demand analysis of a sample case study house with MVHR and of the same case study with naturally ventilation is presented, testing different levels of insulation for each case. Embodied energy data of the additional envelope insulation and the MVHR system is added to the operational energy, and the options are compared from a life cycle perspective.