Housing conditions play a significant role in health. Public health and health care professionals can help residents and communities have healthier housing and better health by connecting them with free weatherization and energy efficiency programs. This document addresses why health professionals should connect residents with energy efficiency programs and how to make that connection. The tool describes the health and economic benefits of energy efficiency services and the array of free energy efficiency services available in California, including eligibility criteria. The guide also provides an in-depth description of a pilot project led by Contra Costa Health Services to connect its medically vulnerable clients with energy efficiency services. The document details lessons learned from that project, as well as from other projects across the country. The guide includes a simple 8-step plan for setting up a system to connect vulnerable residents with energy efficiency services and features such tools as a flow chart for coordination across programs and sample home assessment questions.