What does "air changes" refer to in HVAC systems?

"Air changes" in HVAC systems refers to the number of times the air in a particular space is completely replaced with fresh air within a specified time period, typically measured in hours. This concept is crucial for understanding air quality and ventilation requirements in indoor environments. Regular replacement of stale air with fresh air helps maintain proper indoor air quality, dilute contaminants, and provide adequate oxygen levels for occupants.

In residential or commercial settings, the rate of air changes can affect comfort levels, health, and energy efficiency. For example, spaces that are densely occupied or have high levels of pollutants produced (like kitchens or laboratories) may require a higher number of air changes per hour to ensure a safe and healthy atmosphere.

Understanding air changes assists HVAC professionals in designing systems that not only meet comfort settings but also comply with regulations regarding indoor air quality and ventilation standards. Knowing this is essential for optimizing performance and ensuring the efficient operation of HVAC systems.