Climate analysis has shown tremendous potential of using evaporative cooling in a hot and dry climate. This research reports a case study where amulti-stage evaporative cooling system is installed as the sole summer cooling system in a high performance classroom, located in Boise, Idaho.Initial analyses through design stages suggest that the installed system alone is sufficient to provide cooling with considerable energy savingscompared to a standard forced air system. But the field responses from instructors and students in the classroom indicate otherwise. The gapbetween the actual performance and the expected one at design stages is significant.

This study aims to identify causes why the installed direct and indirect evaporative cooling systems underperform though post-occupancy dataanalysis. Nine months' worth of field performance data have been collected through the installed sensor systems, including indoor and outdoortemperatures and relative humidity, and temperatures at different positions within the direct and indirect evaporative cooling system. Various dataanalyses are conducted to answer the following questions: (1) is the classroom thermally comfortable based on measured temperature and relativehumidity? (2) is the multi-stage evaporative cooling system operated as designed? (3) how does the installed evaporative cooling system perform inBoise, Idaho as compared to similar systems under similar climate? (4) what are the potential causes that make the installed systemunderperform? This case study is intended to expand general understanding of evaporative cooling systems working in a hot and dry climate andprovide valuable feedback and guidelines for future design with a similar system.