BY THE NUMBERS
• $314,169: Construction cost for green roof
• $27,000: Design cost
• $20,000: Estimated annual electric cost for council building
Dave Crockett thinks he can shave at least $4,000 a year from the power bill for the City Council building.
Council members are willing to let him try. On Tuesday, they voted 8-1 to hire Madison, Tenn.-based Two Rivers Roofing Inc. to construct a "green" roof on the building next to City Hall.
"We want to prove it and let this be a laboratory for all buildings downtown," said Crockett, director of the Office of Sustainability.
Deborah Scott was the only no vote. She said she couldn't justify paying $341,000 for a vegetation-covered roof when a standard roof would cost only about $80,000.
But Crockett said the city will save money over time. Power savings are estimated at 20 to 30 percent of the annual power bill and the roof is expected to last 50 years.
The green roof also will earn credits on city stormwater fees, he said.
Monitors will record energy savings and measure how the roof stands up to various kinds of weather, Crockett said.
"We will absolutely have data," he said.
Construction should begin around June, he said.
The City Council building will be the second public building with a green roof -- Outdoor Chattanooga has the other.
Council Chairwoman Pam Ladd said the roof needed replacing anyway and the green cover is eligible for federal grant funding.
She said it fits with city initiatives such as the Outdoor Chattanooga building and the new fire station on Cummings Highway. Both are Leadership in Energy and Environmental Design certified, a designation given to "green" buildings.
Ladd said she thinks the savings over the long term will make up for the front-end cost.
"We'll be measuring it, and we'll be watching it," she said.