Effect of Star Rating Improvement of Residential Buildings on Life Cycle Environmental Impacts and Costs

A diagnostic framework is proposed to assess the influence of star rating improvement for residential buildings on life cycle environmental impacts and life cycle costs (LCEI and LCC) using life cycle assessment (LCA) and life cycle costing methods, respectively, on all life cycle phases (i.e., construction, operation, maintenance, and disposal). A reference house was modified on the basis of six alternative designs to deliver a particular star rating in order to demonstrate the analysis framework. Two LCIA methods (i.e., material flows/add masses and eco-indicator 99 Australian substances) were used to estimate ten LCEI indicators under two categories: seven from problem-oriented (i.e., raw material, air emission, water emission, eco-toxicity, acidification/eutrophication potential, ozone depletion, and climate change) and three from damage-oriented (i.e., resource depletion, ecosystem quality, and effect on human health) categories. The three damage-oriented indicators were combined to evaluate environmental and economic wellbeing on a single eco-point basis. All these combinations of impact indicators can offer three lines of analytical options along with star rating: problem-oriented, damage-oriented, and a variety of problem and damage-oriented LCEIs with LCCs. Hence, the optimum house selection is-based not only on cost or star rating, but also on LCEIs.