Case based analysis on potential benefits of changing Sri Lankan office buildings towards green rated building designs

Abstract

Office buildings are one of the main categories of buildings which possess a rapid growth rate in the context of urbanization. They contribute to a major part of energy consumption in commercial building sector. Even though, the need of adopting energyefficient

features arises, the higher initial construction cost and the myth of longer payback period have been made barriers to this movement. Hence, this study focuses on identifying possible energy-efficient strategies, and their economic performance during the life cycle of the building, to perform an Life Cycle Cost (LCC) to compare the total costs incurred in the conventional office building and a green building and to select the best design that ensures the lowest overall cost with high-quality functions. This study consists of 10 randomly selected low-rise office buildings located in the commercial capital of Sri Lanka, Colombo. Followed by the preliminary survey conducted, it was recognized that high initial cost and the longer payback period was the main two hurdles for the office building owners to move towards the energyefficient

buildings. A conventional office building possesses a 140,000200,000LKR/m 2 of LCC, and a Building Energy Index (BEI) of around 250 kWh/m . Thereafter, based on a defined energy efficient strategy these buildings were developed as energy efficient buildings in 4 stages. Accordingly, it was concluded that stage 4 platinum level energy efficient building is the best design for a low life cycle cost, and it results in a payback period of 3-4 years, 20%-30% of increment in initial construction cost, 30%-40% increment of maintenance cost and 20%-25% reduction of building LCC compared to the conventional office building design.