Carbon Lighthouse implemented a project that is saving an average of $22,900 per year in utility costs – the equivalent of earning 5 months of rent from a 1,000-sf unit (at $60/sf/month) per year – and paid no upfront costs by utilizing PG&E’s on-bill financing, which spreads costs over 5 years. Sansome and Pacific Investments will save $275,100 over the life of the project.
The project reduced annual energy use in the building by 98,300 kWh and 4,000 therms of natural gas. This will reduce carbon emissions by 250 tons per year, the equivalent of planting more than 5,821 trees per year, every year, for the duration of the project savings (12 years).
The Nuts & Bolts: Our Process
Carbon Lighthouse engineers deployed a network of sensors into all of the major building systems to gather deep insight into functionality. These sensors collected millions of data points over the course of multiple weeks. Using this and other data (weather, utility etc) and working closely with facilities staff in the building, a number of cost effective solutions were identified.
Our engineers discovered that the heating and cooling system had broken economizers on all floors and the supply air volume was controlled with discharge dampers, a highly inefficient way for the system to operate. Our engineers had all economizers repaired and VFD’s installed on the supply and return fans. Additionally, the condenser water loop and cooling tower were running even when compressors were not required. With properly operating economizers, controls were installed to turn on the central system only when the air handler required it, providing significant savings. Additionally, we retrofitted a number of light fixtures from T12s to T8s for added savings and improved maintenance.
The project at 755 Sansome provided significant savings to Sansome and Pacific Investments and also helped them achieve their environmental goals by completely eliminating their carbon footprint.