Selection of Efficient Retrofit Scenarios for Public Buildings

Over the past two decades, the importance of the management of existing buildings is continuously increasing with time. Refurbishment of buildings requires execution of various measures that have to be carefully chosen, as selection of a set of refurbishment actions demands that the goals of contemporary sustainable development are achieved. Therefore, a rational decision model is required to select a set of refurbishment measures for a building that results in largest total benefit to cost ratio. This ratio has to be calculated on the basis of several relevant criteria. The basic criteria are identified in this paper as life cycle costs of the building and its structural safety. In Slovenia, an important component of the latter criterion is earthquake resistance, while life cycle costs are predominantly linked to energy consumption of the building. Development and justification of the multi-criteria decision model is presented in the next step. The use of the model is limited to buildings in public ownership. The model takes into the account the fact that refurbishment measures carried out in the present result in reduced operation and maintenance costs over the remaining service life. Life cycle costs reduced due to building energy retrofit have a major impact upon the environmental and economic performance of the building during its operation, while the earthquake resistance improvement (since it decreases the probability of lost human lives) has primarily social impact.