Across a variety of energy conservation programs and tools, energy data visualizations are common components used to inform and influence behavior. Several studies have explored map-based energy data visualizations and found that they compare favorably to conventional charts and graphs, but all generated more unanswered questions about how, when, and why map-based visualizations work well. This research reviews the current state of knowledge and adds to the limited empirical work on map-based energy displays in order to articulate best practices and support broader use of maps to visualize energy data. Two online experiments were conducted with over 830 participants from Amazon Mechanical Turk to assess and compare the usability of multiple versions of map-based energy displays and bar charts. Results were consistent with past research findings that map-based energy data visualizations are more interesting and enjoyable than more basic displays (bar charts). These findings support a general use case for map-based energy displays when trying to engage a broad audience, including those unfamiliar with energy data, by telling a richer story and elevating the data to be more than a set of metrics. Results also highlight the importance of interactivity for map-based energy displays; participants who used interactive features were more accurate in interpreting energy data than those who did not. Other best practices for map-based energy data visualizations are discussed, including considerations for single-variable heat maps, proportional symbol maps, and dual-encoded proportional symbol maps. 

Key words: energy conservation, energy data visualizations, map-based energy displays