Life Cycle Cost Analysis of External Walls in Residential Building for Temperate Climate: A Comparative Study of AAC and CSEB block

Abstract

The use of green building material is one of five design principles proposed by UN Habitat in the year 2013 for Nepal. The construction industry is rapidly evolving and has surmounted difficult economic and technical obstacles in recent decades due to high cost. Operational savings of buildings can be recover the initial construction cost is still a debatable topic. Nevertheless, the implementation of sustainable building practices is still at its lowest edge. This paper aims to empirically examine the above question by conducting a life cycle cost analysis of residential building that utilizes green building material by evaluating the Life Cycle Costs, Construction Costs, operational cost, Residual and maintenance cost for AAC, CSEB solid walls of a single family detached house in Tokha Municipality within a 60 years perspective for temperate climate. Preliminary Bill of quantity (BOQ) was prepared to estimate the amount of material that will be used to construct the base house according to 2019 market Prices. Activity Based life LCC model was used to calculate the Life cycle costing. Autodesk Ecotect Analysis software was used to calculate total heating and cooling load and later converted into operational cost. Lastly, the total initial cost of construction was transformed into life cycle cost model in spreadsheet. Detail Financial analysis was conducted to determine the economy of residential building. And finally alternative wall system was proposed. It was found that the LCC, CC of residential buildings are NRs (Nepalese Rupees) 483.13/m2 and 420.06/m2 respectively for conventional external solid walls with no significant influence on operational cost. The result shows that construction cost contributed to 69% to 75%, maintenance cost contributed 0.03% to 0.43% while repair and reusable costs varied from 0.08% to 0.04%.Similarly, for AAC solid walls it was found to be 478/m2 with initial construction cost at 74.41% and CSEB solid walls it was 539.18/m2 with construction cost contributing to 65.54%.Also the NPV of CSEB block masonry is less than AAC block walls by 46 %.