A comprehensive framework for assessing the life cycle energy of building construction assemblies

Environmental decision making during the building design process has typically focused on improvements to operational efficiencies. Improvements to thermal performance and efficiency of appliances and systems within buildings both aim to reduce resource consumption and environmental impacts associated with the operation of buildings. Significant reductions in building energy and water consumption are possible; however often the impacts occurring across the other stages of a building‘s life are not considered or are seen as insignificant in comparison.

Previous research shows that embodied impacts (raw material extraction, processing, manufacture, transportation and construction) can be as significant as those related to building operation. There is, however, limited consistent and comprehensive information available for building designers to make informed decisions in this area. Often the information that is available is from disparate sources, which makes comparison of alternative solutions unreliable and risky. lt is also important that decisions are made from a life cycle perspective, ensuring that strategies to reduce environmental impacts from one life cycle stage do not come at the expense of an increase in overall life cycle impacts

A consistent and comprehensive framework for assessing and specifying building assemblies for enhanced environmental outcomes does not currently exist. This paper presents the initial findings of a project that aims to establish a database of the life cycle energy requirements of a broad range of construction assemblies, based on a comprehensive assessment framework. Life cycle energy requirements have been calculated for eight standard residential construction assemblies integrating an innovative embodied energy assessment technique with thermal performance simulation modelling and ranked according to their performance.