The HVAC Design Engineer did not accept the concept of varying the air volume to meet theoccupied space demands until he was forced to look seriously at energy conservation. Temperature,ventilation and humidity control, it was believed, could only be assured with constantvolume systems where the temperature and humidity conditions of the incoming air were adjustedto meet the space controller demands. The concept of varying air volume to meet the occupiedspace needs, obviously, has a tremendous impact on the overall system. The HVAC designerwill now size the systems to take full advantage of load diversity instead of the peak demandbasis. The result is smaller.