The potential for setting limits on cooling set-points for air-conditioned UK office buildings

Broadly, this PhD tests the hypothesis that “Limits can be introduced in cooling set-points of UK office buildings without compromising occupant thermal comfort and satisfaction”.

HVAC accounts for around 50% of energy use in non-domestic buildings, and cooling in buildings is likely to increase significantly due to climate change and growing user expectations. A few countries worldwide - most famously Japan with CoolBiz - have introduced limits on minimum cooling set-points in air-conditioned buildings. 

Guidelines from the British Council for Offices, in turn informed by desk-based research, suggests that UK offices could be kept at 24 oC (+/- 2  oC) without excessively compromising thermal comfort or productivity. Yet there is limited data on the current summer thermostat settings maintained in existing air-conditioned (AC) UK offices.

Furthermore, whilst most research on thermal comfort is based on cross-sectional studies, the effect of changing indoor temperatures in existing buildings has not been studied widely - whereby the role of habits and expectations might play an important role. 

With a combination of intervention studies, an online questionnaire of facility managers and in depth interviews with relevant stakeholders (e.g. facility managers, HVAC designers), this PhD aims to:

1. Determine the current level(s) of summer thermostat settings in AC UK offices;
2. Assess to what extent the way in which the temperature change is communicated (or not) in intervention studies may affect the acceptability of thermal conditions (expressed by the occupants in terms of thermal comfort and satisfaction);
3. Establish facility manager’s views on the introduction of policies limiting cooling set-points, as well as understand how decisions are made on setting or changing cooling set-points in UK offices.