English Title



Retrofit, Energy efficiency, Climate change, Dwellings, Thermal comfort, Overheating, United Kingdom.


Architecture | Business | Engineering | Life Sciences


This paper aims to find an optimum retrofit scheme utilising adaptation and mitigation techniques to a Sub-urban English old house, for an inevitable future climate change. It seeks its aims by investigating the energy performance, as well as the summertime comfort of old dwellings in current and future weather predictions. Studies shows that pre-1990 building stock represents one of the least energy-efficient, as these houses were built before the introduction of building envelope directives in building regulation. Specifically, uninsulated semi-detached houses of the inter-war period can potentially be an essential target for retrofits to reach the 2030 carbon emission goal. Previous researches showing the influence of warming climate on energy consumption and indoor comfort have been frequently explored in academic papers. Nevertheless, reviewed investigations were based on archetypal homes and not on a calibrated model. A sensitivity analysis examining current and future heating demand compared to building envelope main parameters was made to define two retrofit scenarios, the light retrofit scheme and the high retrofit scheme (LR and HR).

Study results show that anticipated hotter temperatures have a significant effect on energy consumption and thermal comfort, especially in retrofit models using highly insulated building envelope. Warmer climate conditions can lead to a decrease in space heating and rise in cooling demand; however, heating demand remains predominant. The study also shows that the moderate retrofit scheme (LR) can achieve more than 80% of energy reduction made in the higher retrofit scheme (HR).

The study reveals that overheating risk is very probable in the near future and shows that the pre-retrofitted dwelling demonstrates risks of overheating even in current weather. The occurrence of overheating in future weather data is inevitable, primarily when assessed against TM59 overheating assessment. However, overheating mitigation through adaptation strategies showed a better overheating evaluation in the light retrofit (LR) scheme compared to the high retrofit (HR) one. It is concluded that most of the energy reduction is conceived when applying the light retrofit scheme while potentially having better summertime comfort than the highly retrofitted one. The research recommends that in order to further establish a well acknowledge retrofit strategy, a greater sample size of dwellings of the same archetype is required. Further study over predicted embodied energy calculation and cost-effectiveness of the LR and HR, compared to their actual and predicted operational energy savings, can potentially materialise the idea of a light retrofit scheme.





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