Deep Energy Retrofits are residential remodeling projects, which attempt to drastically reduce energy usage and environmental impact, as well as increase occupant comfort and improve indoor air quality. With energy reduction targets ranging from 50% to 90%, these projects use similar strategies to those typically deployed in a net-zero energy home. Most Deep Retrofits include insulation upgrades, window replacement, air sealing, HVAC replacement, renewable energy technologies, and new appliances and lighting. No building system or component is overlooked. 10 of these exciting projects are being monitored in California by the Energy Performance of Buildings Group at Lawrence Berkeley National Lab. Electrical and gas end uses are sub-metered, providing high resolution data on energy usage patterns in these exciting and diverse projects. Descriptions of these case studies will include the main retrofit measures, design strategies, successes and failures. Partial-year data is available for most of the homes. Don't miss this exciting presentation, which will show how energy is being used in some of California's most cutting edge, energy efficient homes.