In this chapter, two case studies are presented to illustrate the various analysis procedures presented throughout this book. ˜e case studies include a walkthrough energy audit and a detailed energy audit of detached single-family houses. In the reports for the two audit types, typical ‘ndings are outlined as well as the basic procedures used to measure the energy performance of the buildings, including tests to estimate building air leakage characteristics. ˜e reports also present analysis methods to estimate energy use and cost savings from several energy conservation measures. In particular, the results of a series of economic analyses are presented for the two case studies to assess the cost-ešectiveness of the identi‘ed energy conservation measures.