PhD project within Smart City & Smart Buildings


Lucile Sarran,
Industrial PhD


Saint-Gobain Nordic,
Technical University of Denmark, DTU Byg



Technical installations in new and renovated homes, such as heating and mechanical ventilation, are developed and installed on the basis of energy efficiency targets, and have at the same time a large impact on the inhabitants’ comfort and well-being. They are often opaque and increasingly complex, which may lead to discomfort issues and unnecessary energy use.

This project investigated residential heating and ventilation systems from the end-users’ perspective, using methods from engineering and anthropology. Through a questionnaire, interviews and indoor climate measurements, the research uncovered occupants’ experiences and expectations regarding these systems, and the reasons for possible issues – both technical and non-technical. In a second phase, different solutions to the observed problems were examined, looking at two tracks: identifying non-physical drivers of occupant satisfaction that could inform the design of future building systems and interfaces; and developing an automated fault detection and diagnosis tool for residential heating systems.


  • Heating and ventilation systems in low-energy homes, new or retrofitted, suffer from a number of installation and setup faults which can prove detrimental to comfort and energy efficiency. The responsibility for detecting these faults often lies on occupants’ shoulders, but they lack information and guidance to do so.
  • Besides indoor environmental quality, occupants’ comfort and satisfaction are influenced by the usability of the interfaces, the amount of information they received, their perceived degree of control over the indoor climate, and how the technical installations interfere with their daily activities. These factors should be taken into consideration when designing and operating heating and ventilation systems in homes.
  • Occupant satisfaction should be systematically mapped out after move-in, using updated post-occupancy evaluations focusing both on indoor environmental quality, energy use and the non-physical drivers of satisfaction highlighted above. Adopting tools and knowledge from the social sciences into design practice could greatly contribute to improving end-users’ experience in low-energy homes.


Sarran, L., Gunay, H.B., O’Brien, W., Hviid, C.A., & Rode, C. (2021). A data-driven study of thermostat overrides during demand response events. Energy Policy, 153, 112290.
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Sarran, L., Lex, S. W., & Wærsted, E. H. (2021). Comfort and technical installations in low-energy homes: reconnecting design intention and domestic perceptions. Building Research and Information, 1920362.
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Sarran, L., Rode, C., & Hviid, C.A.. (2021). Low-energy retrofitted homes from their occupants’ perspectives: indoor environmental quality and satisfaction with heating and mechanical ventilation systems. In Proceedings of IAQ 2020 conference (accepted).

Building Green, Realdania & Innovationsfonden, Building Green Copenhagen 2020 – Learning Lessions; Smart Buildings & Smart Cities
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Sarran, L., Christensen, M. H., Hviid, C. A., Radoszynski, A. M., Rode, C., & P. Pinson, (2019). Data-driven study on individual occupant comfort using heating setpoints and window openings in new low-energy apartments – preliminary insights. E3S Web of Conferences111, [04063]. https://doi.org/10.1051/e3sconf/201911104063
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Sarran, L. J., Hviid, C. A., & Rode, C. (2020). Correlation between perceived usability of building services and indoor environmental satisfaction in retrofitted low-energy homes. Building and Environment179, [106946]. https://doi.org/10.1016/j.buildenv.2020.106946
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