To balance comfort and energy savings, the city operates mechanical systems only when needed. In most city facilities Carrollton initiated fixed temperature set points using the EMS. Now thermostat air conditioning settings are maintained between 73 and 76°F, and heat settings are maintained between 68 and 72°.

"Based on the air conditioning industry rule of thumb that there is a 5 to 7 percent cost increase for heating or cooling per degree of set point adjustment; these minor changes to high and low settings make a significant difference," said McDaniel.

"For many city employees, this is a common-sense approach," said Beth Bormann, assistant city manager. "Many of us cope with high utility bills at home and we know firsthand the impact that very high or very low settings have on those bills."

"We know we won't please all employees," added facility services manager Carl Shelton. "But it is reasonable for us to maintain a comfortable range while simultaneously managing our costs."

Not only have these energy efficiency measures lowered total energy costs, but they have provided environmental benefits for Carrollton and the North Texas region. By decreasing the city's energy consumption, emissions from area power generating plants are also reduced.

"The energy saving measures cut annual carbon dioxide emissions by approximately 257 tons," said McDaniel. "This is equivalent to taking 366 cars off the streets of Carrollton each year or planting 497 acres of trees."

Publication date: 11/20/2006