How many air changes per hour are considered sufficient for healthy indoor air quality?

An air change rate of 2-6 air changes per hour is widely recognized as sufficient for maintaining healthy indoor air quality. This range helps to ensure adequate ventilation, which is essential for removing indoor pollutants, controlling humidity levels, and providing fresh outdoor air.

When air changes occur within this range, it allows sufficient time for contaminants to be diluted and replaced with cleaner air. A rate lower than this could lead to the accumulation of pollutants, which may negatively impact health over time. Conversely, rates significantly higher than this might not be necessary for effective air quality management and could result in higher energy costs without substantial benefits.

In many indoor environments—like offices, schools, and residential buildings—this 2-6 threshold is practical, balancing ventilation efficiency and energy use while promoting overall health and comfort.