Building age as an indicator for energy consumption

Current energy consumption estimates for building stocks rarely use measured data. Calculated data of supposed representative buildings are extrapolated to a wider building stock. Conclusions drawn about supposed similar energy consumption levels risk being misleading when considering older buildings. The chosen approach is based on detailed morphological information of the building stock of a Swiss city, and of the final energy consumption (gas) of all buildings in two districts. The basic data provided from a number of different sources were aggregated in a GIS-based depository. An unbiased analysis of the building stock reduces the risk of misinterpreting consumption patterns and of adopting inappropriate renovation strategies, which could lead to the irreversible loss of tangible and intangible values. The findings of this contribution question the general explanatory power of typologies as a priori classifications by construction age and dwelling type. Using an evidence-based methodology, the significance of all available building attributes were analysed to decide if classification is at all a.feasible method, and, if so, which aspects should be considered. A statistical method (CHAID) showed that there is a strong interdependence between energy consumption, compactness, and building age. Buildings constructed before 1921 performed better than the stock average. Buildings built between 1947 and 1979, which constitute the largest share of stock, performed worse. Better knowledge and understanding of the actual energy performance of the stock could foster differentiated planning policies; primarily focusing on those-segments of the building stock with high energy saving potentials. This would allow adapting renovation targets for other more vulnerable segments of the stock. The approach presented here could facilitate a controlled improvement of the existing stock, and allow identifying both successful and less successful renovation strategies. (C) 2014 Elsevier B.V. All rights reserved.