Energy saving strategies included an improved building envelope, 100% LED lighting, high efficient water cooled chillers and high efficient condensing boilers. The building automation system was utilized to develop efficient control strategies to drive energy usage down even farther. This can only be done by truly understanding the building occupancy and the intended use. An example of optimizing system and building operations includes the use of VRF split systems to cool the data and electric rooms. This allowed for the central plant and AHUs to be shut down at 6:00 PM, while maintaining the space temperatures in critical spaces. Fan Powered VAV boxes were used on all exterior zones, which provide unoccupied hours heating, while the larger AHUs remained off. CMTA also provided the HVAC system commissioning services, to make sure the building operated as intended. Lighting is 100% LED lighting, for reduced maintenance, and low energy use. The average lighting intensity is 0.38 watts per square foot, which is 61% below the code allowed levels for lighting intensity.
The building achieved a LEED v 2009 Silver certification, mainly due to the 15 energy points earned as part of Energy and Atmosphere Credit 1 – Optimized Energy Performance. By utilizing LED lighting, an Innovation Credit was earned for eliminating mercury in the light fixture lamps. The building also achieved an Energy Star score of 100.
After tracking the building for a year of post occupancy, the building has performed better than expected. Traditionally, 4 pipe VAV systems operate at a EUI of 50 to 75. The Sower 300 State Office Building is operating at a EUI of 28.6 and an energy cost index (ECI) of $0.60.