Comparing environmental impacts from energy and materials embodied in buildings and used during their service life

Models calculating the environmental benefits of renovation and retrofitting of buildings are generally based on energy calculations and don’t take into account the environmental penalty of demolishing and replacing parts of the building and its equipment. The environmental effect embodied in these activities is negleted and only the environmental benefits of a lower building related energy use are taken into account. In addition, energy use cannot be considered an environmental problem in itself, but causes several environmental impacts, which are not necessarily linearly related to the energy use. In this paper, the author studies the relative values of the embodied environmental impacts and the operational environmental impacts, as well as the relationship between energy use and environmental impacts. The calculations are based on a tool for energy use calculations and on EcoQuantum, a tool for life cycle assessment. Results are presented in terms of environmental payback times. The results are discussed and clarified based on two case studies. Recommendations are made about the necessity of a dynamic simulation procedure.