US-based Carbon Lighthouse has completed an efficiency retrofit of San Francisco's Flood Building, a local landmark built in 1904.
Upgrades in the 12-story building are expected to yield tenants combined savings of $1m over the next 15-years.
Work included the installation of a computerised central management system, the addition of an improved HVAC system and a number of lighting improvements.
Combining these efforts should eliminate 870 tonnes of carbon dioxide per year.
Jim Flood, building owner, said, 'In addition to saving our tenants money on their utility bills, this project makes a significant dent in our building's carbon footprint.
'Carbon Lighthouse's work aligned with our mission to preserve the integrity of this historic space while modernising our operations as much as possible. Even better, the project was smooth and stealthy, and posed no disruption to the day to day business of our tenants.'