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Predicting energy savings of the UK housing stock under a step-by-step energy retrofit scenario towards net-zero. [Dataset]


Jamal Alabid
Data Collector

Richard Laing
Data Collector


Space and water heating for UK homes make up 25% of total energy use and 15% of greenhouse gas emissions. To meet the UK’s ambitious goal of reaching zero emissions from existing buildings in the UK by 2050, by 2030, UK homes’ emissions need to fall by at least 24% from 1990 levels. In 2017, there were some 28.5 million homes in the UK, and the great majority of these were in England. The UK has one of the least energy efficient housing stocks in Europe, resulting in high energy bills and a large number of households affected by fuel poverty, fundamentally owning to space heating. The current practice in retrofit policy decisions and studies in the UK have been focused on the single-step building retrofitting approach to predict energy savings and carbon reductions of the housing stock. While one-stage deep renovation allows for fast CO2 reductions once the retrofit takes place, studies have presented empirical evidence that step-by-step retrofit is a practical and logical approach in real-life scenarios. The literature review did not identify any model covering the step-by-step retrofitting focusing on interdependencies between the retrofitting steps, and that is the main contribution of the present paper to the existing literature. The present paper aims to determine the energy-saving potentials achievable throughout the UK housing stock with step-by-step renovation targeting the EnerPHit standard.


BENNADJI, A., SEDDIKI, M., ALABID, J., LAING, R. and GRAY, D. 2022. Predicting energy savings of the UK housing stock under a step-by-step energy retrofit scenario towards net-zero. [Dataset]. Energies [online], 15(9), article 3082. Available from:

Acceptance Date Apr 21, 2022
Online Publication Date Apr 22, 2022
Publication Date May 1, 2022
Deposit Date Apr 25, 2022
Publicly Available Date Apr 25, 2022
Publisher MDPI
Keywords Net zero; UK housing stock; Step-by-step energy retrofit; EnerPHit; Building typology; Energy-saving
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Related Public URLs
Type of Data PDF file (Annexe).
Collection Date Mar 17, 2022
Collection Method The methodology used to apply the building typology approach to predict energy savings of the UK housing stock under a step-by-step energy retrofit scenario consists of different steps: first, the UK national residential building typology is created. Then, the energy balance of the UK residential buildings is calculated and validated against national statistical data. Finally, a building stock retrofit plan specifying the order in which to apply energy efficiency measures is elaborated, and the energy savings are calculated. In this paper, the building types developed by BRE as part of the participation of the UK in the European project EPISCOPE were used to represent the housing stock of the UK for their geometric data, construction, and thermal systems features. The energy-related properties of dwelling types in Wales, Scotland, and Northern Ireland were assumed to be the same as for England. There are 32 UK residential building types in the EPISCOPE, split by eight construction periods (i.e., pre–1919, 1919–1944, 1945–1964, 1965–1980, 1981–1990, 1991–2003, 2004–2009, post–2010) and four building sizes, including Single-Family House (SFH), Terraced House (TH), Multi-Family House (MFH), and Apartment Block (AB). For the research presented in this paper, the number of building types was further reduced due to the lack of data regarding the housing stocks in Scotland, Wales, and Northern Ireland. The construction periods 1981–1990, 1991–2003, 2004–2009, and post–2010 were merged into one construction period, which is post–1980, resulting in 20 building typologies. The SAP assessment tool was used following EnerPHit step-by-step methodology for retrofitting a wide range of housing typologies, with recommendations on how to improve building envelopes and systems in a cost-effective way. Improvements for existing UK housing have been suggested to be taken step-by-step in a medium-term plan, starting with the fabric first approach, as recommended by PAS2035. The existing housing structure and construction detailing was derived from the Tabula database on UK housing stock, with amendment according to current housing statistics, as Tabula counts the structural detailing as built in the first place. However, renewable options were limited to installing photophobic panels, which only considers the south-oriented roof area. The five improvement steps follow the EnerPHit and PAS2035 recommendations for a medium-term retrofit plan that considers sequencing and unintended consequences. This has been referred to as the risk management strategy in PAS2035, so that there will be no reverse impact of implementing certain measures on other health or energy aspects. Replacing windows with high efficiency and air-tight sealings will reduce infiltration air, which will result in a decrease in draught air, with a risk of less ventilation. Therefore, ensuring sufficient fresh air supply is necessary to maintain this balance. It is also recommended that replacing windows should be carried out prior to EWI whenever possible to ensure that windows are installed within the insulation layer for avoiding thermal bridge occurrence. The characteristics of the building typologies and the characteristics of retrofit steps considered in this paper are summarised in the accompanying file to this output.


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