Currently, houses do not perform optimally or even as many codes and forecasts predict, largely because they are field assembled and there is no consistent process to identify deficiencies or to correct them. Solving this problem requires field performance evaluations using appropriate and agreed upon procedures in the form of a new process called residential commissioning. The purpose of this project is to develop and document these procedures and to demonstrate the value that applying them could provide in both new and existing California houses. This project has four specific objectives: to develop metrics and diagnostics for assessing house performance, to provide information on the potential benefits of commissioning using a whole-house approach, to develop programmatic guidelines for commissioning, and to conduct outreach efforts to transfer project results to industry stakeholders. The primary outcomes from this project are the development of residential commissioning guidelines and the analytical confirmation that there are significant potential benefits associated with commissioning California houses, particularly existing ones. In addition, we have made substantial advances in understanding the accuracy and usability of diagnostics for commissioning houses. In some cases, we have been able to work with equipment manufacturers to improve these aspects of their diagnostic tools. These outcomes provide a solid foundation on which to build a residential commissioning program in California. We expect that a concerted effort will be necessary to integrate such a program with existing building industry efforts and to demonstrate its use in the field.