According to California Department of Finance estimates, as of January 2008 the state had over 13.4 million residential dwellings. Multifamily housing units make up 4.1 million units, or almost one third of California’s total housing stock. Older existing housing have a considerably larger environmental impact than dwellings built under today’s standards. Estimates indicate that energy efficiency improvements alone in California’s older housing stock could save up to 25,807 gigawatt hours of electricity and 972 million therms of natural gas each year. These increases in efficiency could reduce greenhouse gases by 13.7 MMTCO2e per year.
Multifamily dwellings have significant opportunities to increase efficiency, especially in the areas of water heating, space heating, and lighting, which collectively account for 72% of total site energy consumption (excluding common area loads such as pool heating) and landscaping, the main source of water consumption.
Increasing the sustainability of the existing multifamily residential sector presents a tremendous opportunity for reducing energy and water consumption statewide. Utility programs, such as those highlighted in the case studies to the left, have demonstrated that retrofits in multifamily buildings can reduce energy usage by 20% or more and reduce their environmental impact and improve their attractiveness for current and potential tenants. A significant portion of these savings can be achieved through simple, low cost measures and sound operating and management practices that can achieve significant cost savings for property owners, managers, and tenants.