A fuzzy reasoning cost estimation model of sustainable building refurbishment solutions for residential buildings in Hong Kong

Abstract

The global climate has been affected adversely due to the emissions of large amount of greenhouse gases (GHGs) and there is an urgent need for emissions reduction. Carbon dioxide is a major greenhouse gas and the reduction of its emissions is indispensable to the achievement of sustainable development. The building sector is a major source of carbon dioxide emissions and one way to reduce the emissions is uplifting the energy efficiency of existing buildings by conducting sustainable building refurbishment. As cost would affect the decisions on sustainable building refurbishment strategies, it is necessary to examine the cost of various sustainable refurbishment solutions for existing buildings. Unfortunately, most of the previous studies focused on the technical side with little effort being directed to cost side. Therefore, cost analysis of sustainable building refurbishment solutions should be conducted to fill the research gap.

The aim of the research is to develop a cost estimation model to facilitate decision makers to evaluate the cost of sustainable building refurbishment solutions for residential buildings in Hong Kong by considering various factors affecting the cost. The major research methods include literature review, interview and questionnaire survey. Through literature review, the current practice of sustainable building refurbishment is investigated. A variety of refurbishment solutions including improvement on building envelope, renovation of building services system and the use of renewable energy are reviewed. Cost evaluation techniques commonly used in the construction industry including qualitative techniques, quantitative techniques and intelligent methods are also identified and discussed. Due to the limitations of cost data and previous experience, it is suggested that fuzzy logic theory be adopted to develop the cost estimation model.

To facilitate the development of the model, the factors affecting the cost of sustainable building refurbishment solutions are examined through literature review and interview. It is found that market price, complexity, efficiency, economy of scale and disturbance are the dominant factors affecting the fluctuation of cost. Finally, a fuzzy reasoning cost estimation model of sustainable building refurbishment solutions is developed. The model is built based on fuzzy reasoning system. Users can input the information of the project and the model is able to evaluate the cost fluctuation based on the information provided by the users. The model is then validated.

The cost estimation model developed in this research provides a new way for the construction industry practitioners to estimate the cost of sustainable building refurbishment projects effectively and efficiently.