Energy Performance

Energy Performance
Cumulative (vs. Baseline)-8%
Annual (2016)-17%

Better Buildings Challenge Partners strive to decrease portfolio-wide source energy use intensity (EUI) and to increase the percent improvement compared to a set baseline. The City of Chattanooga's portfolio consists of more than 190 buildings covering  2 million square feet and one wastewater treatment plant (WWTP). Since 2013, Chattanooga has improved energy performance by 10% in buildings, however, when including the city’s WWTP, cumulative performance decreased by 8%. Although Chattanooga has implemented a variety of energy conservation measures at the plant resulting in an EUI reduction, below average rainfall and influent flow negatively impacted the portfolio EUI in 2016. This relationship between water flow and energy use has incentivized the city to explore additional optimization opportunities at the WWTP. Building energy savings have been achieved by implementing a retrocommissioning program and upgrading the HVAC controls at the City Hall campus, recreation centers, and other larger city buildings to allow remote scheduling and management of the building systems. Building on the early success of the retrocommissioning program the city is able to make strategic improvements to building systems and upgrades to lighting and lighting controls that stand to move them well along to their goal for energy use reduction.


Looking at the percent improvement in energy performance across all buildings can provide insight into how an organization is saving energy.  The City of Chattanooga has achieved energy performance improvement of greater than 10% at more than 40 of its buildings with several of the city's properties experiencing even greater energy performance improvements. Although at this early stage, there are 25 buildings that have experienced an increase in Source EUI, armed with the key performance metrics provided through utility monitoring in Portfolio Manager, the city is able to shift its focus on strategic improvements to the lowest performing properties that will result in the greatest energy performance payback for the capital invested.


Property-level energy performance metrics, including EUI and percent improvement to date, are critical to track progress over time and identify opportunities for additional energy savings. Chattanooga's building portfolio consists of a wide range of property-types which results in a portfolio with a wide range of baseline EUI values. While the majority of the city of Chattanooga buildings have shown energy improvement since the baseline of 2013, the properties located near or below the 0% axis may indicate properties that present good opportunities for further improvement in energy performance and savings.