Energy Retrofit
Area: Design, planning and building
Buildings are responsible for approximately 40% of energy consumption and 36% of greenhouse gas emissions in the EU (European Commission, 2021). Energy retrofit is also referred to as building energy retrofit, low carbon retrofit, energy efficiency retrofit and energy renovation; all terms related to the upgrading of existing buildings energy performance to achieve high levels of energy efficiency. Energy retrofit significantly reduces energy use and energy demand (Femenías et al., 2018; Outcault et al., 2022), tackles fuel (energy) poverty, and lowers carbon emissions (Karvonen, 2013). It is widely acknowledged that building energy retrofit should result in a reduction of carbon emissions by at least 60% compared with pre-retrofit emissions, in order to stabilise atmospheric carbon concentration and mitigate climate change (Fawcett, 2014; Outcault et al., 2022). Energy retrofit can also improve comfort, convenience, and aesthetics (Karvonen, 2013).
There are two main approaches to deep energy retrofit, fabric-first and whole-house systems. The fabric-first approach prioritises upgrades to the building envelope through four main technical improvements: increased airtightness; increased thermal insulation; improving the efficiency of systems such as heating, lighting, and electrical appliances; and installation of renewables such as photovoltaics (Institute for Sustainability & UCL Energy Institute, 2012). The whole-house systems approach to retrofit further considers the interaction between the climate, building site, occupant, and other components of a building (Institute for Sustainability & UCL Energy Institute, 2012). In this way, the building becomes an energy system with interdependent parts that strongly affect one another, and energy performance is considered a result of the whole system activity.
Energy retrofit can be deep, over-time, or partial (Femenías et al., 2018). Deep energy retrofit is considered a onetime event that utilises all available energy saving technologies at that time to reduce energy consumption by 60% - 90% (Fawcett, 2014; Femenías et al., 2018). Over-time retrofit spreads the deep retrofit process out over a strategic period of time, allowing for the integration of future technologies (Femenías et al., 2018). Partial retrofit can also involve several interventions over time but is particularly appropriate to protect architectural works with a high cultural value, retrofitting with the least-invasive energy efficiency measures (Femenías et al., 2018).
Energy retrofit of existing social housing tends to be driven by cost, use of eco-friendly products, and energy savings (Sojkova et al., 2019). Energy savings are particularly important in colder climates where households require greater energy loads for space heating and thermal comfort and are therefore at risk of fuel poverty (Sojkova et al., 2019; Zahiri & Elsharkawy, 2018). Similarly, extremely warm climates requiring high energy loads for air conditioning in the summer can contribute to fuel poverty and will benefit from energy retrofit (Tabata & Tsai, 2020). Femenías et al’s (2018) extensive literature review on property owners’ attitudes to energy efficiency argues that retrofit is typically motivated by other needs, referred to by Outcault et al (2022) as ‘non-energy impacts’ (NEIs). While lists of NEIs are inconsistent in the literature, categories related to “weatherization retrofit” refer to comfort, health, safety, and indoor air quality (Outcault et al., 2022).
Worldwide retrofit schemes such as RetrofitWorks and EnerPHit use varying metrics to define low carbon retrofit, but their universally adopted focus has been on end-point performance targets, which do not include changes to energy using behaviour and practice (Fawcett, 2014). An example of an end-point performance target is Passivhaus’ refurbishment standard (EnerPHit), which requires a heating demand below 25 kWh/(m²a) in cool-temperate climate zones; zones are categorised according to the Passive House Planning Package (PHPP) (Passive House Institute, 2016).
References
European Commission. (2021). 2021/0426 (COD) DIRECTIVE OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL on the energy performance of buildings (recast). https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:52021DC0550&from=EN
Fawcett, T. (2014). Exploring the time dimension of low carbon retrofit: Owner-occupied housing. Building Research and Information, 42(4), 477–488. https://doi.org/10.1080/09613218.2013.804769
Femenías, P., Mjörnell, K., & Thuvander, L. (2018). Rethinking deep renovation: The perspective of rental housing in Sweden. Journal of Cleaner Production, 195, 1457–1467. https://doi.org/10.1016/j.jclepro.2017.12.282
Institute for Sustainability, & UCL Energy Institute. (2012). Retrofit strategies. Key Findings: Retrofit project team perspectives. https://www.instituteforsustainability.co.uk/uploads/File/2236_KeySummary03.pdf
Karvonen, A. (2013). Towards systemic domestic retrofit: A social practices approach. Building Research and Information, 41(5), 563–574. https://doi.org/10.1080/09613218.2013.805298
Outcault, S., Sanguinetti, A., Dessouky, N., & Magaña, C. (2022). Occupant Non-Energy Impact Identification Framework: A human-centered approach to understanding residential energy retrofits. Energy and Buildings, 263, 112054. https://doi.org/10.1016/j.enbuild.2022.112054
Passipedia: The Passive House Resource. (n.d.). EnerPHit – the Passive House Certificate for Retrofits. Retrieved 11 April, 2022, from https://passipedia.org/certification/enerphit
Passive House Institute. (2016). Criteria for the Passive House, EnerPHit and PHI Low Energy Building Standard. www.passivehouse.com
RetrofitWorks. (n.d.). RetrofitWorks: Building Energy Efficiency Together. Retrieved 11 April, 2022, from https://retrofitworks.co.uk/
Sojkova, K., Volf, M., Lupisek, A., Bolliger, R., & Vachal, T. (2019). Selection of favourable concept of energy retrofitting solution for social housing in the Czech Republic based on economic parameters, greenhouse gases, and primary energy consumption. Sustainability (Switzerland), 11(22). https://doi.org/10.3390/su11226482
Tabata, T., & Tsai, P. (2020). Fuel poverty in Summer: An empirical analysis using microdata for Japan. Science of the Total Environment, 703. https://doi.org/10.1016/j.scitotenv.2019.135038
Zahiri, S., & Elsharkawy, H. (2018). Towards energy-efficient retrofit of council housing in London: Assessing the impact of occupancy and energy-use patterns on building performance. Energy and Buildings, 174, 672–681. https://doi.org/10.1016/j.enbuild.2018.07.010
Created on 23-05-2022 | Update on 20-09-2022
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