A team of mayors and nonprofit foundations said Wednesday that they’ll spend enough retrofitting major U.S. cities to save more than $1 billion per year in energy costs. Former New York Mayor Michael Bloomberg’s philanthropy, the Doris Duke Charitable Foundation, and the Kresge Foundation pledged $3 million each year for three years to provide technical advisers for 10 cities across the country: Atlanta, Boston, Chicago, Denver, Houston, Kansas City, Los Angeles, Orlando, Philadelphia and Salt Lake City. The City Energy Project, as it’s called, is intended to cut 5 to 7 million tons of carbon emissions annually, or roughly the amount of electricity used by 700,000 to 1 million U.S. homes each year. The Natural Resources Defense Council and the Institute for Market Transformation will help the cities draft plans to reduce waste and improve energy efficiency—a process the group said should not take more than one year. Chicago’s participation could lower energy bills by as much as $134 million annually and could cut about 1.3 million tons of greenhouse gas emissions annually, according to the mayor’s office. In a prepared statement, Mayor Rahm Emanuel said the investment would create jobs: “More energy efficiency means new jobs and continued economic growth, and a more sustainable City,” Emanuel said, “which will lead to a further increase in the quality of life for the people of Chicago.” Last year Illinois tightened its building code and Chicago ordered large buildings to disclose their energy use. In Chicago, like many of the nation’s older cities, large buildings eat up much of the city’s energy—together the buildings sector accounts for 40 percent of primary energy consumption in the U.S. While energy efficiency has long been recognized for its financial opportunity, major banks have only recently begun to invest. Los Angeles Mayor Eric Garcetti said he hopes City Energy Project will connect building owners and private financiers, bringing more money to large-scale efficiency initiatives.