The importance of life-cycle based planning in maintenance and energy renovation of multifamily buildings

Abstract

Improving the energy performance in the real estate sector has become increasingly important and drawn a lot of attention during the past few decades. Despite all the technological developments, the energy efficiency measures are yet expensive and when implemented only to improve the energy performance, are rarely economically justified. To lower the costs of energy performance improvements, an alternative is to combine energy efficiency measures with already required renovation measures. The problem with renovation on the other hand, is that its planning is not strategic; it is mainly opportunistic, short-term and with the focus on the capitalization of newly-discovered opportunities, meaning that renovation measures are coupled when one or more of the rather costly building components have reached failure. The take on an opportunistic approach, however convenient, results in loss of value which is most often neglected in the economic evaluation of renovation projects. The lack of strategic planning and the subsequent loss of value become more important in less-attractive markets, where there are both budget constraints and socio-economic issues. Energy performance and/or living standard are often sacrificed through improper distribution of resources as the choice of renovation measures are often influenced by the return of investment. Therefore, a proper evaluation of renovation alternatives not only can satisfy the technical and financial requirements but also help maintain proper living standard and improve the energy performance in multifamily buildings. In a prior study, authors have proposed a systematic approach to cost-optimal maintenance and renovation planning by combining the deterioration function of building components with respective service-life cycle costing. This paper presents an extension of that methodology to include the energy efficiency option pricing as an optimization criterion. The extended methodology is meant to provide support for housing owners in building management in forms of technical and economic evaluation of possible energy-renovation scenarios under time/budget constraints. To demonstrate the application of the methodology, maintenance/renovation plans are devised for three building components with sharing fixed costs (windows, faöade and roof) in both new and existing multifamily buildings.