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The energy-saving potential in buildings (e.g. buildings proposed for an energy upgrade in an energy policy context) is often overestimated because implicit factors, such as rebound effects, are ignored. In order to get an accurate estimate of the realisable energy-saving potential in a building stock, these factors, as well as how they differ among buildings with different characteristics, must be accounted for.On the building stock level, detailed information about the actual conditions in each building (e.g. indoor temperatures, domestic hot water consumption, internal heat loads, etc.) is rarely available. In its place, fixed assumptions are often made, usually disregarding the characteristics of the buildings. Therefore, a method that is based on available building stock data is needed for adjusting this technical energy-saving potential.This study investigated how the heat consumption in residential buildings might be expected to change due to an energy upgrade, using a hybrid bottom-up model of the Danish residential building stock. Pseudo-rebound effects, inherent to the thermal standard of the building, were quantified in a sample of 134.000 buildings with different characteristics.Results showed that estimating the heat-saving potential on the basis of the thermal characteristics alone (i.e. the technical heat-saving potential), would lead to a considerable overestimation of the realisable heat-saving potential in the residential building stock. However, the size of the realisable heat-saving potential was found to vary considerably among buildings with different characteristics, despite having the same technical potential. This indicated that the technical heat-saving potential should be corrected differently in buildings with different characteristics.

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The residential building stock holds a large saving potential related to energyupgrading of the building envelope. Heterogeneous details about building characteristics are paramount to perform a proper assessment of attractive heatsavings measures. Based on a sample of buildings, the study develops methods to identify saving potentials for heterogeneous building-tailored heat-saving measures and evaluates their cost-effectiveness in the framework of a district heating area in Denmark. The study accounts for rebound effects and develops both technical (gross) and more realistic (net) potentials, allowing a more accurate analysis of attractive heat-saving measures. The analysis is novel as it rely on modelling actual building characteristics rather than synthetic archetypes, which can lead to loss of diversity (e.g. in variation of costs and potentials) and thereby discarding cost-effective potentials. The analysis also investigates the results sensitivity to assumption about the discount rate and focuses on the effect of different district heating tariffs, on the total cost-effective investments.The outcomes show that cost-effective measures vary considerably, in size and type, among building categories, based on energy performances certificate labels (EPC). When all the cost components are variable, the total cost-effective potential increases considerably, with specific measures distributed differently among building categories, with the cost components providing different incentives to invest. Heterogeneity thus does matter, when evaluating economically attractive investments in heat-saving measures.

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