The building at 220 Montgomery St. is owned and operated by the locally based The Swig Co. Its environmental program for the building included physical improvements such as efficient lamping, installation of motion sensors, daylight harvesting, and equipment retrofitting, along with process improvements such as green cleaning practices and recycling programs. The Energy Star is given to buildings that use at least 35% less energy than average buildings while still meeting its tenants' power needs.

Organizations earn the Energy Star by using the EPA's national energy performance rating system to generate energy-efficiency ratings for their buildings, on a scale of one to 100 relative to similar buildings across the country. The rating system is available for office buildings, schools, dormitories, hotels, hospitals, and grocery stores, among other commercial buildings. The Mills Building is one of 3,200 buildings nationwide that have earned an Energy Star from the US EPA.

Across the Bay, 365 Main Inc. is reducing energy consumption at its datacenter in Oakland by more than 1.67 million kilowatt hours, enough energy to power approximately 242 homes each year. To achieve the reduction, the locally based company participated in a new program called Savings By Design. The program is funded by California utility customers and administered by Pacific Gas and Electric Co., San Diego Gas and Electric, Southern California Edison Co., Southern California Gas Co., and the Sacramento Municipal Utility District.