Connected devices like the Nest Learning Thermostat provide an unprecedented amount of data about home energy usage patterns. This data can be used to further our understanding of how homes really work, and to help us identify both opportunities for and barriers to improving home performance. This session will present insights gleaned from analyzing large-scale anonymized data collected by Nest thermostats, and discuss the significance of these insights for the home performance industry. Topics to be addressed include: variations in HVAC run times with weather, real-world sizing of heating and cooling equipment, indoor temperature and humidity variations by season, and heat pump performance characteristics.