Energy and thermal comfort evaluation of mass-custom prefabricated buildings

Purpose This research examines energy use and thermal comfort in 116 mass-customized prefabricated buildings in Western Europe. Building component U-values ranged from 0.12 to 1.70 W/m2K, with an average floor size of 85.1 m2. The main goal is to evaluate energy performance across seasons and contribute to knowledge on thermal comfort and energy assessment, focusing on mass-prefab buildings using various methods. Design/methodology/approach The methodology involved measuring environmental variables, conducting post-occupancy evaluations (POE), thermal comfort surveys and analyzing energy data. Surveys were given to residents in monitored houses, while energy data were collected there. POEs were done in both monitored and unmonitored houses. A total of 218 questionnaires were completed from the surveys and POEs. The data were analyzed using different statistical tools. Findings Indoor temperatures ranged from 22.6 °C to 23.7 °C in summer and 17.5 °C–19.3 °C in winter. Respondents felt near neutral in winter, warmer (4.5/7.0) in summer. Winter’s neutral (Tn) and preferred (Tp) temperatures were 0.3 and 4.3 °C higher than in summertime. Winter had higher thermal acceptability and satisfaction. Annual gas use ranged from 10,496 to 12,114 kWh, with about 50% of buildings exceeding energy limits and all exceeding electricity benchmarks. Practical implications The study identified factors like occupancy behavior, duration, thermal awareness and ownership that influence building energy use. It showed that well-designed, energy-efficient mass-custom prefabricated buildings – considering space, orientation, insulation, appliances, passive solar, renewable energy and more – can significantly reduce energy consumption. This aligns with UN Sustainable Development Goals (SDGs) 3, 7, 11 and 12 by improving residents’ thermal comfort, well-being and low-carbon energy performance buildings. Originality/value This study innovatively uses diverse methods to examine energy use and thermal comfort in mass-customized buildings across seasons, aiming to boost future performance. It highlights the need for more research on energy evaluations during design to better understand interventions that improve building performance and involve key stakeholders like builders, investors, scientists and policymakers. The mass-custom sector can significantly promote sustainable environments by balancing occupant comfort with energy efficiency.