Multi-criteria assessment of the scenarios of changing the heating system in apartments in historical buildings in Wroclaw (Poland) – Case study

Abstract

The aim of this study was to carry out a detailed examination of the situation in 15 premises in buildings built before World War II in three variants: existing condition, standard use and standard use after modernization. The proposed multi-criteria assessment method made it possible to compile on one scale the results of the analysis of very different criteria (emission, energy consumption for heating, energy costs, comfort of using the premises). It was found that in 9 tested premises the energy costs and the impact on the natural environment were lowered by drastically reducing the comfort of use. Significant differences were shown in the assessment of the effects of thermal-modernization depending on the reference level. The average reduction of energy costs after modernization in relation to standard use is 41%. Whereas, the reduction of costs in relation to existing condition is on average 2%. Thanks to an in-depth analysis, it was found that even after modernization, there is a risk of improper use in 5 premises, e.g. further underheating of the premises as a result of high operating costs. However, including all criteria in the assessment, the overall situation of tested premises after modernization condition improves by on average 60%.