Prior to these studies, no estimates of national consumption were known to exist. Although studies are ongoing, some interesting preliminary information has been forthcoming. The collective parasitic energy is of equal importance to the heating and cooling energy consuming elements in a building. Packaged systems use the most parasitic energy. System Type and Building Type Parasitic energy use in commercial buildings has been determined for various types of HVAC systems.
Percentages represent the portion of the total parasitic energy consumed.
Data have also been gathered on the total parasitic energy consumed in the building by various building types. The percentage of the total energy consumed in the building attributed to the parasitic energy category is increasing. This increase is attributed to several factors. Because of improved chiller efficiencies, the chiller portion of the total energy consumed in the building is decreasing, which in turn increases the importance of the contributions of other energy areas in the building. Added filtration and smaller distribution ducts have increased fan energy.