This document provides an overview of the Heating Ventilation and Air Conditioning (HVAC) module of the ECBC Training Workshop. It discusses key concepts in HVAC including whole building design approach, non-refrigerative and refrigerative cooling techniques, HVAC system types, components and efficiency metrics, building commissioning, and ECBC requirements. The document is intended to educate professionals on best practices in HVAC system design and operation to improve energy efficiency in buildings.