When used with the ACC-DSEN supply air sensor, the unit enables contractors to troubleshoot their ColorTouch® thermostat clients’ HVAC units from virtually anywhere via the Internet. Supply air monitoring features include the ability to compare supply-duct temperature to the thermostat’s current heating or cooling demand, to the actual room temperature, and to the outdoor air temperature. The unit also displays high and low supply-duct temperature history (resets automatically at midnight).