The Impact of Different Insulation Options on the Life Cycle Energy Demands of a Hypothetical Residential Building

Abstract

Selecting materials that are energy efficient over their life cycle at the early stage of a design is dependent upon numerous parameters that make determination of all their impacts on the environment difficult. Choice of thermal insulation options for a building's external walls significantly affects its life cycle energy demands. However, the accurate impact analysis of different insulation options from a life cycle energy assessment (LCEA) viewpoint is influenced by numerous interrelated parameters and is generally too complex for designers to determine in the early material selection stage of design. The aim of this paper is to highlight this complexity by using the example of an evaluation of the LCEA of 18 different forms of thermal insulations that vary in type and thickness for a multi-storey residential building in Sydney, Australia. The sensitivity of the results to the Window to Wall Ratio (WWR), as an another effective variable on the building's operational energy demands, is then analysed.The study indicates that different thermal insulation options of external walls have a marginal impact on the building cooling energy demands in Sydney's climatic zone, whereas they significantly affect the heating energy demands. In addition, changing of insulation options produce significant increases in the embodied energy. The impact of various WWRs on the building's operational energy changes the result of the optimum and the least efficient choices among the 18 insulation options.Overall, the example highlights that it is not possible to quantify all the effective parameters in selecting materials in terms of designing an energy efficient building through its life cycle. This paper is part of a larger research project attempting to simplify the LCEA and enable designers to identify the most effective variables on a building's life cycle energy demand when selecting materials at the early design stage.