In August 2012, the historic Mills Building at 220 Montgomery Street in downtown San Francisco received a LEED Gold certification, making it the city’s oldest official LEED-certified structure. Originally designed and built in 1892 by Chicago architects Burnham and Root/D.H. Burnham & Company, the 10-story, 450,000-square-foot building, notable for its subtle Romanesque detailing, is owned by The Swig Company, which is headquartered in the building and manages more than nine million square feet of office space across the country.
Regarding the decision to undergo a LEED overhaul, Chris Wong, property manager for the building, says, “The Swig Company purchased the building in 1954, so the Mills Building has a lot of history for the family. We’ve always recognized the importance of keeping the building up to date with various sustainability initiatives.”
In 1974, the Mills Building was added to the National Register of Historic Places, so it is not only a high-profile building in the Bay Area architectural landscape but also the oldest in Swig’s portfolio. An in-depth energy consultation performed by Leading Edge Consulting helped inform the overhaul, which led to a building-wide adaptation of an energy-management system, allowing for the building managers to better moderate usage and expenditure. “This system, which has especially altered the lighting in the building, is really helpful because it began to give us a way of quantifying our savings,” Wong says.
Aided by the energy-management system, which is used partly to respond to strict demand-response requests, lighting in the corridors and public areas is managed by the system, and high-intensity lighting is being replaced with low-energy LED options. The LEED overhaul also created daylight-harvesting opportunities in the elevator lobbies. Lighting automation features are included in the building’s 220 tenant spaces, which range from 200 to 42,000 square feet. “We’ve seen a significant drop in our electric costs with the changes in these lighting systems,” Wong says. “We’ve also slowed down the speed of our elevator cabs. We have 12 passenger cabs, and we’ve seen a lot of energy savings here with no decrease in tenant satisfaction for elevator speed.”
The building also includes temperature moderators for its steam fittings, where it gathers its heat and then reduces stress on the boilers by allowing for better temperature moderation.
With a designation of LEED Gold, the Mills Building is the third LEED-certified building in Swig’s portfolio. The Kaiser Center Building, in Oakland, California, and the 180 Montgomery Building, across the street from the Mills Building, also have LEED Gold certifications, but the Mills Building is the company’s only historical building to have it. As Wong says, “The overhaul has given us a great way to bring the old architecture into the new world.”