Energy savings versus thermal comfort in existing Mediterranean office buildings: a case study assessing the effectiveness of low-impact retrofit strategies

Purpose Energy retrofit strategies based on non-invasive or minimally invasive measures are widely adopted in existing office buildings; however, their effectiveness is often assumed to be transferable across different climatic contexts. This study investigates energy savings and thermal comfort obtained by using commonly applied low-impact retrofit actions in existing Mediterranean office buildings. Design/methodology/approach A dynamic simulation model of an existing office building located in Southern Italy was developed to evaluate the impact of non-invasive retrofit measures, including indoor air temperature setpoint adjustments, daylight saving time strategies and the replacement of conventional boilers with air-to-water heat pumps. Energy performance was assessed in terms of heating, cooling and lighting demand, while thermal comfort was evaluated using Fanger theory. Findings The results show that setpoint adjustments provided the highest individual savings (up to 4.8%), followed by heat pump adoption (4.0%), while their combined application led to a maximum reduction of 7.7%. These savings seem limited since they refer to total annual primary energy consumption, but savings related to heating can reach up to 24–46%, while those related to cooling reach 18%. Moreover, a clear trade-off between energy savings and thermal comfort was identified, particularly during winter conditions. Research limitations/implications The analysis is based on a simulation model without calibration against measured data, although a good consistency with available benchmark data for office buildings has been obtained; therefore, results should be interpreted as a comparative assessment rather than absolute predictions. Practical implications The findings support decision-making in the management of existing buildings, highlighting both the potential and limitations of low-cost retrofit strategies. Originality/value The study provides an integrated evaluation of low-impact energy retrofit strategies, identifying a significant trade-off between energy savings and thermal comfort for existing Mediterranean office buildings.