An HVAC system consists of an air handler supplying conditioned air (mixture of return air...

A multiple-zone system is a system that has one or more air handlers supplying conditioned air to more than one zone. A zone is a space or group of spaces within a building with heating and cooling requirements that are sufficiently similar so that desired conditions (e.g., temperature) can be maintained throughout using a single controlling device. The ventilation rate procedure calculations must be based on the multiple-zone system configuration because the HVAC system in the question serves different zones with different ventilation requirements. References : LEED V5 Reference Guide for Building Design and Construction, p. 688 1 ; ASHRAE Standard 62.1-2010, Section 6.2.5 2