A study was conducted in the Pacific Northwest region (Oregon, Washington, Idaho, and western Montana) to measure ventilation characteristics in electrically heated single-family, detached residences during the 1987-1988 and 1988-1989 heating seasons. This study generated information that will be used to develop energy conservation programs for Northwest homes. This data will be used to evaluate the cost effectiveness of various conservation measures, to establish residential building codes, and to help regional power planners in making decisions about the management of the Northwest's electrical resources.