Thermal comfort and perceived air quality (PAQ) using automatic ceiling fans in residential buildings

In warm climates, resilient and low-energy methods for cooling building occupants are needed to ensure energy-efficient and adaptive thermal comfort. Air movement, particularly through ceiling fans, is an effective way to provide comfort in warm conditions, potentially minimizing or even avoiding the need for more energy-intensive air conditioning systems. This study aims to validate an algorithm for automatically adapting ceiling fan speed in residential settings based on room thermal conditions and focuses on subjective thermal satisfaction and perceived air quality (PAQ). An environmental chamber study was conducted with 30 participants across three different indoor air temperature conditions (27 °C, 29 °C, and 31 °C) over 2-hour sessions, testing four fan operational modes: Automatic (downward flow), Manual Direct (downward flow), Manual Reverse (upward flow), and Off. Subjective thermal satisfaction and PAQ were measured using standardized questionnaires on a 7-point Likert scale. Results showed that automatic operation maintained comparable thermal satisfaction levels to manual control, with no statistically significant differences (p > 0.3) across all temperature conditions, indicating that the automatic algorithm successfully provided comfortable environmental conditions comparable to user-controlled settings. Direct flow mode (downward) significantly outperformed reverse flow mode in thermal satisfaction, especially at higher temperatures (29 °C and 31 °C, p < 0.05). Air movement in direct flow improved perceived air quality compared to the no fan condition across all temperatures (p < 0.05). Automatic fan control showed no difference in PAQ satisfaction across all temperature conditions (p > 0.2), while manual and off modes showed decreased satisfaction, particularly from 27 °C to 31 °C (p < 0.05). These findings demonstrate that automatic ceiling fans can achieve equivalent comfort satisfaction to manual operation while enabling a more energy-efficient alternative to traditional air conditioning. The validated automatic control system provides a practical pathway toward resilient and personalized cooling strategies in residential buildings, contributing to both climate change mitigation and the achievement of plus-energy building goals.