What does the term "air exchange" refer to in HVAC?

The term "air exchange" specifically refers to the process of replacing indoor air with outdoor air. This process is essential for maintaining good indoor air quality, as it helps to remove stale air, odors, and pollutants while bringing in fresh air from outside. Effective air exchange can also help regulate humidity levels and temperature within a building, creating a more comfortable and healthier environment for occupants.

Understanding air exchange is crucial in HVAC systems as it ensures that both ventilation and air quality standards are met. Systems that facilitate this process might include mechanical ventilation systems, which are designed to bring in a specific volume of outdoor air based on the size and occupancy of the space. This is a fundamental aspect of HVAC design, especially in tightly sealed buildings.

The options that focus on recirculating indoor air, heating air indoors, or cooling outdoor air do not address the concept of replacing indoor air, which is the core meaning of air exchange. Each of these processes serves a different purpose within an HVAC system but does not capture the overall significance of air exchange in maintaining indoor air quality.