Optimizing the Life Cycle Costs of Building Components with Regard to Energy Renovation

Abstract

Considering the high share of residential buildings in the total energy use in Sweden, having the ambitious national energy and climate goals in mind, the real estate sector and its issues have been under a lot of attention during the past few decades. The Swedish real estate sector has often been identified with its ambitious public housing program during the record years (1960–1974). This was at the time the largest housing program per capita in the world where more than a million apartments were built in a nation with a population of 8 million. These apartments once being the pride of a nation, are facing a lot of problems today, ranging from vacancy and unacceptable physical condition to very poor energy performance. These buildings at the verge of their service/economic life are in need of extensive maintenance and renovation measures. Considering the technological development today, the problem with maintenance and renovation remains to be the financial constraints. These are what makes planning for maintenance and renovation complicated and cost inefficient. Although there are tools that can help property managers with maintenance and renovation planning, they all fail to address the complexity of the decision-making process in a multi-objective criteria under financial and time constraints. In this study, the focus is on the life cycle economy of the building components subject to energy performance improvements during renovation. A systematic approach has been proposed that can be used to budget and plan renovation with regard to energy efficiency under budget constraints. This approach utilizes a modified condition/deterioration model of the method Schroeder to simulate the maintenance effect on the condition state of building components in order to obtain the cost-optimal maintenance regime under given restrictions. This methodology can be used to compare the cost effectiveness of different energy-renovation scenarios and determine the optimal renovation plan for a single or a combination of buildings with regard to owners’ objectives and existing constraints. The results from this study illustrates how prioritizing action plans can affect the life cycle costs of building components.