With respect to load types, there are three major loads in commercial buildings: HVAC, lighting and plug loads. According to the data from EIA published in 2008 , electricity use by HVAC equipment, i.e., space heating, cooling and ventilation accounts for 30% of the total electricity consumption in buildings. Lighting loads constitute the majority share of electricity use at 38%. Electricity use by plug loads, i.e., office equipment, computers, etc. accounts for 6% of total electricity use in buildings. Other loads include water heating, refrigeration, elevators, etc. The figure below illustrates electricity use in buildings by load type.