Extreme heat events can stress the electrical grid and jeopardize customers’ energy reliability. In September 2022, California had an unprecedented heat wave and customers were asked to reduce energy consumption over four days to avoid rolling black outs. During this time, Sacramento Municipal Utility District (SMUD) communicated to customers via a variety of channels and rolling black outs were avoided. Six weeks following the extreme heat event, SMUD evaluated the content, frequency, and channel of communication with customers. An on-line survey was sent to sub-set of SMUD customers (n = 3349, response rate of 4%). Energy conservation was strongly correlated with email readership over the week, six emails were sent to customers with an average open rate of 46%. Respondents were grouped into five segments based on self-reported daily energy conservation, e.g., 52% of respondents strongly agreed that they reduced energy usage during the 4-day heat wave. Self-reported behavior was triangulated with meter data (cooling degree hours), with varying results. We also investigated respondent’s psychographics using the Schwartz Value Scale. Those who claimed they conserved the least energy were highest in values emphasizing tradition and security while those that conserved the most were highest in benevolence and universalism. Those that saved the least energy were more likely to be motivated to prevent electricity disruption to their own home but not to save money on their energy bill. Demographically, they were more likely to be renters, lower income, had lower insulation levels, and did not have programable thermostats. Results also identified high-value conservation behaviors and potential message framing to increase uptake across different types of customers. Proactively pilot testing messages is essential for effective communication during future emergency situations.