The potential for introducing minimum cooling set-points in air-conditioned offices : a UK case study

• Main Author: Lakeridou, M.
• Published: University College London (University of London) 2017
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.746987

This action research dissertation investigates the potential of introducing a minimum summer cooling temperature of 24°C within UK air-conditioned offices (British Council for Offices (BCO)recommendation). Increasingly more UK offices use air-conditioning and 2050 projections include 100% air-conditioning penetration. Adjusting current socio-cultural norms by raising cooling set-points is one way of avoiding this trajectory. Countries such as Japan have introduced limits to office cooling to reduce their carbon emissions. This research commenced by investigating the implementation of the BCO recommendation to offices which are not BCO certified. Intervention studies in four UK air-conditioned offices were conducted. Findings suggest that raising the set-point from 22°C/23°C to 24°C may not significantly affect occupants’ self-reported thermal comfort, but may cause complaints encouraging a return to original settings. A significant variation in temperatures across and within floors with the same set-point was detected, highlighting the practical challenge of regulating temperatures via set-points. Possibly due to this challenge, the most effective form of communication to facilitate occupant acceptance of set-point changes could not be established. Findings from the intervention studies were used to inform the subsequent studies: (i) a questionnaire for 91 Facility Managers (FMs) and (ii) 22 interviews with FMs and other actors. FMs perceive a government policy on cooling set-points as a more effective driver than a recommendation. The interviews suggest that often, FMs reactively change set-points based on isolated complaints, and there is no standard practice for set-point ‘ownership’ and governance. Some FMs view themselves as mediators between occupant/senior management expectations and building capabilities. This dissertation articulates the research journey and critically discusses the challenges encountered in conducting workplace/real-world interventions. This research reveals that many offices are cooled below 24°C. However, raising set-points in existing buildings is not straightforward and may be affected by factors not currently acknowledged in thermal comfort standards, including leases, FM knowledge and perception of occupant needs, occupant expectations and senior management support. This research highlights the need for developing best practice guidance on set-point governance and handling of thermal complaints. Further research is needed on the role and expectations of senior management and other actors in driving set-point regulation.