What does the term 'ventilation rate' describe?

The term 'ventilation rate' specifically refers to the amount of outside air that is supplied to a building, which is determined in regard to the size and occupancy of that space. This concept is crucial in maintaining indoor air quality, as adequate ventilation helps to dilute indoor pollutants and ensure a supply of fresh air for occupants.

Proper ventilation rates are usually calculated based on various factors including building codes, occupancy levels, and the types of activities taking place within the building. By maintaining appropriate ventilation rates, HVAC systems can contribute to healthier indoor environments, potentially reducing the risk of airborne diseases and improving overall comfort.

The other options pertain to different aspects of HVAC operation but do not define ventilation rate. Temperature fluctuation relates to thermal comfort success rather than air exchange; efficiency pertains to how well HVAC equipment converts energy into useful work; and humidity levels deal with moisture management, which is a separate concern from the introduction of outside air.