Analysis of Air-Conditioning Usage Behavior in Residential Buildings in Hot and Humid Climates: Evidence from Vietnam

The building sector accounts for about one-third of global final energy consumption, with a significant increase in electricity use related to air conditioning (AC), especially in hot and humid regions. In this context, it is crucial to reduce building cooling demand. Since AC usage is closely related to occupants, it is necessary to consider the impact of occupant behavior when developing solutions to improve energy efficiency in buildings. However, in most studies and design standards, AC usage is assumed to be “full-time and full-space”, resulting in a significant performance gap. As part of the project CAMaRSEC, annual indoor climate data were collected from 82 residential apartments in Hanoi and Ho Chi Minh City, Vietnam. Based on these data, this study provided an in-depth analysis of the characteristics of AC usage. The results indicated that air conditioners were mainly used in bedrooms at night, showing a clear “part-time and part-space” pattern. Significant differences in the intensity of AC usage were also observed across apartments, with the AC turn-on probability closely related to room temperature and time of day. The findings of this paper provide a valuable evidence base for occupant-centric building design and modeling of AC usage behavior.