Retaining a healthy indoor environment in on-demand mixed-mode classrooms

Abstract

A global pandemic has increased focus on indoor air quality and fresh air exchange in mixed-mode buildings where the transition between modes often requires human intervention. A study to measure energy performance and CO2 concentrations was conducted in two Hawai’i classrooms to determine the impact of user decision-making on adequacy of fresh air. Using CO2 as a marker for indoor air quality and fresh air exchange, significantly different CO2 concentrations were observed in the two identical classrooms. This study complements the findings by others who showed classroom ventilation was frequently inadequate, but illuminates the importance of user familiarity with building operation in order to maintain a healthy indoor environment. In the Hawai’i mixed-mode classrooms, ventilation and CO2 levels were dependent upon: user awareness of how fresh air was introduced; user training; availability of operable windows; and outside fresh air supply from the air-conditioning unit.