Goal directed life cycle costing as a method to evaluate the economic feasibility of office buildings with conventional and TI-façades

Transparent insulation systems (TI-systems) of less than 20cm thick have been developed as an alternative to opaque wall insulation and windows, which provide a financial return to building occupants when applied to building façades. Lack of detailed cost analysis of TI-systems is a major constraint to the application of TI-wall and TI-glazing in buildings. A goal directed life cycle costing (LCC) technique and sensitivity analysis used to evaluate the economic feasibility of TI-applications in office buildings form the basis of this research. It was undertaken as part of research to determine optimum energy and cost performance of TI-systems for external cladding of high-rise and low-rise office buildings in temperate and tropical climates. The LCC of the buildings with conventional façades were compared with those with TI-façades. The results show that LCC can be used to evaluate the economic feasibility of low carbon technologies such as TI-systems effectively. A detailed account is provided of how different sources of cost data can be captured, collected and integrated to perform selective goal directed LCC analysis in the absence of detailed historical LCC data. The use of the goal directed LCC method and cost influence diagram presented in this research can be adopted as a standard method for assessing the economic feasibility of applying low carbon technologies to buildings.