This book is for energy auditors or retrofitters, whether they work in the weatherization program or in the private arena, and is intended to help them prepare for several certifications. These include programs with BPI, RESNET-HERS, DOE/NREL, and AEE (Association of Energy Engineers). The material in this book contains industry procedures and techniques and is intended to be an educational resource. Topics covered include the house as a system, the auditor's tools, weatherization, sealants, insulation and barriers, retrofitting, heating and cooling, baseload, and new construction. A number of additional appendices are included to provide the reader with valuable information in the performance of a residential energy audit.