SACRAMENTO -- The Metro Center Office Park in Sacramento will soon undergo a major efficiency upgrade that will significantly lower its utility bills. 

Ygrene Energy is funding the project that will retrofit heating and ventilation for the entire building. Charles McGinnis of Johnson Controls says new rooftop units will be featured.

"They'll be much more efficient, much more reliable during severe weather. They'll provide fresh and conditioned air to the tenant spaces," McGinnis said.

At a cost of more than $3 million dollars, Ygrene CEO Stacey Lawson says it's the largest Property Assessed Clean Energy project in the nation.

"This project shows that the promise of pace is finally here," she said.

Mayor Kevin Johnson says the project perfectly fits into Sacramento's commitment to being the greenest region in the country and a hub for clean technology.