Abstract
It is estimated that buildings in extreme weather regions waste large amounts of money each year in thermal comfort costs, and that if addressed, significant amounts of environmental impacts would be averted. Retrofitting is considered the most immediate, pressing, and effective mechanism for reducing energy consumption and greenhouse gas emissions in the building sector. An environmental life cycle costing was applied to evaluate the sustainability of retrofitting existing buildings. A portfolio of environmental and economic impact results was developed for a baseline building and five alternative retrofitted building scenarios based on insulating the building wall. The results demonstrated a reduction in the environmental impacts and economic impacts by retrofitting the building. Improving the thermal performance of the building resulted in a reduction of environmental life cycle cost of 5%. Externality, which is primarily caused by energy usage, was the key source of the environmental life cycle cost. People in hot climate zones spend much of their time indoors, therefore, it is critical to keep comfortable thermal environment in buildings. This study provides strategically important evaluations for transforming existing buildings into more cost-effective and environmentally friendly sustainable buildings.