SEATTLE (AP) - The new City Hall that was to be an environmentally friendly upgrade from the older, larger building it replaced isn't so energy efficient after all.

The glass-walled structure with its open spaces is using 15 percent to 50 percent more electricity than the old building, according to Seattle City Light utility bills obtained by the Seattle Post-Intelligencer for a report Tuesday.

The bills - $3,000 to $5,000 higher per month than in the old building - are a blow for the city and Mayor Greg Nickels, who has urged cities nationwide to reduce energy consumption and voluntarily comply with the Kyoto environmental protocols.

To its credit, the building uses less water, and less trash is produced each week.

And the building would be using even more electricity without its energy-saving features, which reduce consumption by an average 19 percent, said Jorge Carrasco, City Light superintendent.

"That comparison corrects for all other things," he said.

City Light records show the new building uses 7,045 kilowatt-hours of electricity on average per day, compared with 5,940 kilowatt-hours per day in the old City Hall. Without its energy-saving devices, the new structure would use 8,645 kilowatt-hours per day, City Light estimates.

City Council members, surprised by the $72 million building's high energy use, immediately began searching for culprits.

"If this is true, then there is something wrong," Councilman Richard Conlin said. "Maybe it's operational. It was definitely supposed to meet higher standards. Maybe the old building was more efficient than we thought."

"Did each council office come with a cute little refrigerator in the old building?" said Jean Godden, chairwoman of the council's energy and environmental policy committee who pointed to the small fridge in her office closet.

"In the old building, the elevators were so slow everyone took the stairs. Maybe that has something to do with it."

The new, smaller City Hall opened in 2003 to replace the 1960s-era building. Its air conditioning and heating systems primarily use natural gas.

The building features limestone imported from France and a titanium wall that shrouds the council chamber. The materials are meant to help the building last 100 years - with the titanium suggesting the metal used by The Boeing Co. to build its airplanes.

"It was designed to be a building that is much more inviting to the public … beyond what the old municipal building ever was," Nickels spokeswoman Marianne Bichsel said, noting that plans for the new building began under former Mayor Paul Schell. "This is an energy-efficient building."

The building was designed to meet requirements for silver certification under the Leadership in Energy and Environmental Design program. A request for certification was sent last month to the U.S. Green Building Council.

Certification considers all aspects of a building's design, including materials used, water and energy efficiency, natural light, views, landscaping and how a building is oriented on the site.

"Energy efficiency is a big part of LEED," said Gwyn Jones, a spokeswoman for the Green Building Council.

The certification process doesn't audit actual performance of the building or how much energy it uses.