ENERGY AND LIFE CYCLE COST SAVING POTENTIAL OF BUILDINGS USING GREEN WALLS: A CASE STUDY FROM SRI LANKA

Abstract

With its numerous benefits, the concept of green walls can be used as one of the solutions to address global warming and climatic changes while improving the natural vegetation in dense urban areas. However, perception about the initial and maintenance cost of green walls along with lack of awareness about operational cost savings seems to influence the slow uptake of green wall applications. In that context, this research aimed to assess the Life Cycle Cost (LCC) of green walls in comparison to a conventional wall towards exploring the operational cost benefits which are the most convincing decision criteria for clients/investors. The study involved a case study analysis of an indirect green façade and a comparative conventional wall. The data required to perform the LCC analysis were collected through documentary reviews and on-site temperature measurements. The analysis shows that the initial cost of a green wall is 15% higher than a comparable conventional wall. However, operational and maintenance costs of green walls result in 64% and 25% savings due to potential energy cost-saving, and minimum external redecoration time interval, respectively. This results in an overall LCC saving of 45% over conventional walls with a reasonably expected lifetime of fifty years. As a departing point of previous studies, this study provides empirical evidence on the LCC of green walls in comparison to a conventional wall in a residential facility, from a tropical climate perspective.