Climate Wise is an industrial energy efficiency program sponsored by the U.S. EPA, and supported by the U.S. DOE, working in partnership with more than 400 industrial companies. Many Climate Wise Partners are evaluating or implementing boiler and steam system efficiency measures and have requested assistance in quickly estimating the impacts of these projects through the Wise Line. Climate Wise has developed the Wise Rules for Industrial Efficiency (Wise Rules Tool Kit) to provide companies with simple rules of thumb, or Wise Rules, for estimating potential energy, cost, and greenhouse gas emissions savings from key industrial energy efficiency measures for a broad range of end uses, including boilers and steam systems. This paper presents excerpts from the Wise Rules Tool Kit on boiler and steam system efficiency measures