<p> A formative evaluation of behavior change elements of an ongoing Weatherization Assistance Program (WAP) offered by the Energy Resource Center (E.R.C.) in Denver, CO was conducted. The WAP as administered by the E.R.C. in Colorado saves residents an average 15% of energy consumption (E.R.C., 2015). However, research suggests that adding behavioral components to WAPs could increase energy savings to 21&ndash;26% (Gregory, 1992; APPRAISE, 2002). The goal of this evaluation is to provide recommendations to E.R.C. for program changes using Community Based Social Marketing (CBSM) and Theory of Planned Behavior. The CBSM Step 1- Step 3 is the focus of this formative evaluation. This program evaluation has four components: 1) review of written materials, 2) interviews with staff, 3) surveys mailed to E.R.C. clients and 4) in-home observations conducted with E.R.C. clients. Results of this formative evaluation has 3 sections of behaviors recommended for future intervention high priority, mid priority, and low priority recommendations based on CBSM penetration, probability, and impact factors. Behaviors that are listed as high priority for E.R.C. Behavioral intervention are cold water washing, hang drying, setting back thermostats, and window coverings. Overall increase in staff engagement is also recommended to be pursued. Each staff level is also given recommendations on how to engage in behavior change interventions.</p><p>