HVAC lab is the second step to the understanding of building energy performance. Through the course, the concepts of ventilation, indoor air quality, heat exchangers, HVAC load calculation, HVAC systems, and its components were studied. Enforcing the theoretical knowledge; experiments such as Particulate matter count, Blower door test, HRV installation and measurement, etc. were conducted. Finally implementing and visualizing the impact of the HVAC system and its components with various energy conservation measures, simulations were done, to analyze and understand HVAC system optimization and achieve energy efficiency.