Life cycle assessment of a south European house addressing building design options for orientation, window sizing and building shape

Abstract

The life cycle assessment (LCA) methodology has been extensively used to assess the environmental influence of alternative building construction; however, the influence of building design has seldom been assessed for Mediterranean climate. This article aims to evaluate the influence of three, often neglected, design options on the life cycle (LC) energy and environmental impacts of a south European single-family house: solar orientation, window sizing, and building shape. Using a parametric attributional LCA, the house's materials, construction, maintenance, and operation (heating and cooling) are analysed for different design scenarios. Annual operational energy, LC non-renewable primary energy (NRPE) and environmental LC impact assessment (LCIA) results are presented and discussed. Results show that embodied energy generally surpasses operational energy. Building orientation has less influence on LCIA results than on operational energy, particularly for compact shapes. Scenarios with bigger Window-to-Wall Ratio (WWR) have higher embodied impacts, being more sensitive to orientation due to solar gains. Lower WWR (5%) can be used to reduce the overall LC impacts, especially in houses with lower operational patterns. A compact shape building was shown to reduce heating impact, while a terraced and less compact shape reduces cooling impact. Compared with literature, this study reveals that, from a LC perspective, design options are as significant as construction options. Finally, design recommendations should be based on LCA and not only on operational results; nevertheless, a LCA single indicator (NRPE or Global Warming Potential) can be used to support decisions for alternative house designs with similar construction.