HVAC stands for Heating, Ventilation, and Air Conditioning. It is an essential part of any building plan or design. As the necessity of these items depends upon the weather condition, they vary from region to region; and the symbols of elements also vary in number based on their usage. Some common HVAC elements in a reflected ceiling plan are different types of inlets, outlets, diffusers, etc. Different types of inlet symbols include circular inlet and circular inlet with a flow arrow. Outlet symbols include circular outlet and circular outlet with flow arrows. Some other commonly included element symbols are the thermostat, supply air, return air, grille, ceiling fan, etc. With the presentation of these HVAC items in the reflected ceiling plan, you can easily determine the level of ventilation in the floor or space.