Chattanooga's tallest office building has gone green and garnered the federal Energy Star badge.
The 21-story Republic Centre is the city's first private, commercial office tower downtown to land the designation that cites energy-saving practices, according to the U.S. Environmental Protection Agency.
Only the Edney Building, which the Tennessee Valley Authority owns at 11th and Market streets, has the label downtown, EPA's website shows.
Chattanooga businessman Jim Berry, whose company owns the Chestnut Street structure built in 1976, said he likes happy tenants, and his personnel explained the energy savings that could be achieved.
"I've always attempted to run a first-class building," he said.
Ronnie Williams, senior vice president of the Jim Berry Co., said it's a laborious process to secure the Energy Star, which likely is most commonly identified with efficient appliances.
"It started a year ago," he said. "You've got to give them a lot of data."
Williams estimated that about $1.2 million was spent over a 10-year period to put the building in its current state. He projected a savings of about $175,000 annually.
Among key steps taken was a computer-monitored digital climate control system to help ensure tenant comfort and cut energy use, he said.
"There's a tremendous amount of savings," Williams said.
Also, the original single pane glass panels in the building were modified with interior thermal window film, he said. In addition, adjustable blinds were installed to reduce heat gain but also to allow indirect lighting, Williams said.
Ron Speicher of Metro Services Inc., which partnered with building officials for a long-range upgrade and energy-saving plan, said a recent improvement is the building went from air-cooled to water-cooled chillers.
He said air-handling systems were improved with automatic control valves, variable speed drives, temperature sensors and air pressure monitors to reduce energy use and optimize performance.
Speicher said about 30 office buildings statewide hold the Energy Star label. He said only about four other structures in Chattanooga are Energy Star certified.
Steve Hunt of the real estate firm Berry & Hunt said the Energy Star improvements will help him keep tenants in the building.
"It makes my job a lot easier," he said. "Consumption has gone down even though tenant use has gone up."
Susan Rich of building tenant Baker Donelson said the law firm occupies over three floors of space in the tower.
"They want to help us save money," she said.