The relationship between material service life and the life cycle energy of contemporary residential buildings in Australia

Energy use and related greenhouse gas emissions of buildings have a significant effect on the environment. To reduce energy consumption in buildings, it is important to understand energy use occurring across the building life cycle. While previous studies have shown the significance of both the energy required for building operation as well as the energy embodied in initial building construction, an understanding of the total energy embodied in replacement materials over a building's life is not as well developed. One of the key factors affecting this recurring embodied energy is the service life of materials. The aim of this study was to investigate the relationship between the service life of materials and the life cycle energy demand associated with contemporary residential buildings in Australia. The initial embodied energy, operational energy and recurrent embodied energy of a detached residential building were calculated with material service life values based on average figures obtained from the literature. These values were then varied to reflect the extent of service life variability likely for a selection of the main building materials and recurring embodied energy recalculated for each scenario. Selected materials of the building were then replaced with commonly used alternatives and the building's initial and recurrent embodied energy recalculated for a range of materials service life scenarios. The results from this initial study indicate that the service life of materials can have a considerable effect on total energy demand associated with a building over its life. This demonstrates the need for further clarity around the service life of materials and the importance of considering the durability of materials when designing and managing buildings for improved energy efficiency. Results from this study also suggest the importance of including the recurrent embodied energy of buildings in building life cycle energy analyses, which in this case represented between 19 and 31% of the life cycle energy of the building as built and 21 and 34% with the use of alternative materials.