Optimising choices of 'building services' for green building: Interdependence and life cycle costing

By influencing energy consumption, water use, and indoor environment quality, 'building service systems' are indispensable to green building. In practice, building services are chosen separately by different professions while they are literally interdependent on each other in determining the overall effectiveness and efficiency of green building. In addition, these building services are chosen at the initial stage without necessarily considering their life-cycle costs (LCC). A more holistic view to consider the interdependence of various building services throughout their life cycle is highly desired. Hence, this research aims to examine building services in green building by considering both their interdependence and costs throughout the building life cycle. The Hong Kong BEAM (Building Environmental Assessment Method) Plus is selected for a case study. Initially, the credits related to building services are identified and mapped from the BEAM Plus. Afterwards, LCC of the credits are calculated using the net present value technique. It is discovered that by considering building services' interdependence from a life cycle perspective, the choices of such building services could be much different. A significant proportion of the LCC is related to operation, maintenance and replacement of the building services, which cannot be offset by the savings of green building independently. However, there are benefits such as CO2 reductions, which can be used to make up the LCC if they can be properly monetised. The research provides significant insights to developers and their consultants in choosing cost-effective building services with a view to better realising the value of green building.