Vocabulary
Terms and definitions on affordable and sustainable housing *
Prebound Effect
Area: Design, planning and building
The concept ‘prebound effect’ refers to the phenomenon where actual energy consumption in buildings is significantly lower than the calculated energy consumption needed to maintain comfortable indoor temperatures (Sunikka-Blank & Galvin, 2012). This is typically observed in older, less energy-efficient homes, where occupants often under-heat their homes due to financial constraints, leading to lower actual energy usage than predicted by models (Galvin & Sunikka-Blank, 2016). This contrasts with the more commonly used term ‘rebound effect’, which occurs when energy consumption increases following efficiency improvements, offsetting some of the anticipated savings (Teli et al., 2015). The difference between the two is clearly visualised in Figure 1, developed by Sunikka-Blank and Galvin (2012).
Energy savings discrepancies
The prebound effect leads to significant discrepancies in energy savings estimates for retrofitting projects. Standard models often overestimate energy savings because they do not account for the lower baseline consumption caused by the prebound effect. This discrepancy is crucial because it implies that thermal retrofits may not yield the anticipated reductions in energy use and carbon emissions, which are often overstated in policy and financial analyses (Galvin, 2023).
For instance, in Hungary, research shows that energy consumption predictions are often based on technical data alone, ignoring actual under-consumption behaviours, leading to overestimates in expected savings (Gróf et al., 2022). Similarly, in Italy, studies have highlighted that prebound effects cause a gap between theoretical energy models and actual energy usage, complicating the accurate forecasting of energy savings from retrofits (Giuliani et al., 2016). The study by Van den Brom et al. (2019) also supports this, showing that building characteristics and occupant behavior significantly influence energy consumption, with discrepancies between expected and actual savings due to prebound effects being notable in both the Netherlands and Denmark.
Additionally, Gróf et al. (2022) emphasised that the prebound effect is influenced by the financial status of households, with households having limited financial means more likely to under-heat their homes, resulting in a greater prebound effect and further complicating the prediction of energy savings.
Inherently linked to energy poverty
Therefore, the prebound effect is closely linked to energy poverty, as it often reflects the behaviour of households that cannot afford to heat their homes adequately. Households experiencing fuel poverty are more likely to exhibit high prebound effects due to their efforts to save money on heating (Galvin & Sunikka-Blank, 2016). For instance, social housing tenants in the UK showed significant prebound effects, leading to under-heated homes and reduced energy consumption prior to retrofitting (Teli et al., 2015). Addressing the prebound effect involves recognising and mitigating the financial constraints that lead to under-consumption, thus improving both the accuracy of energy savings predictions and the living conditions of households experiencing energy poverty (Galvin, 2024a, 2024b).
Moreover, hidden energy poverty is a critical aspect of this issue. Households often are not categorised as energy poor based on expenditure-based indicators because they do not dare to put their heating on due to financial constraints (Cong et al., 2022; Eisfeld & Seebauer, 2022). These households minimise their heating to the point where their energy expenditures are deceptively low, masking the severity of their situation. However, more recent indicators that focus on energy efficiency rather than high costs would identify them as energy poor (Betto et al., 2020). Addressing hidden energy poverty requires a shift in assessment criteria, also focusing on the energy efficiency of homes rather than just the high cost of energy bills. This approach ensures that households struggling with inadequate heating due to financial constraints are accurately identified and supported (Croon et al., 2023).
Created on 20-06-2024
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* This vocabulary consists of definitions of key terms related to the combined research conducted by the 15 early-stage researchers. Each term has multiple definitions, each connected to one of the three main research areas: Design, Construction and Planning; Community Involvement; and Policy and Funding.
The joint construction of this vocabulary allows the researchers' projects to be interwoven. As such, the vocabulary is a tool for conducting transdisciplinary research on affordable and sustainable housing.
Entries are reviewed by RE-DWELL researchers and supervisors. The vocabulary is updated regularly.