Field evaluation of a new device to measure air handler flow

The airflow rate in heating and cooling equipment has major implications for the performance of the system. Improper flow across air conditioner and heat pump coils degrades the capacity of the coil, low flow across the heat exchanger in furnaces can cause the system to cycle on the high-temperature limit switch, and the flow rate has major implications for the efficiency of the duct system. The primary method for measuring the airflow through an air handler uses the change in temperature between the return and supply side of the air handler. However, this method is known to have major drawbacks. Recently, a new device has been developed that provides an easy way to measure the flow rate through residential air handlers. This paper presents the results of a field
study to evaluate the performance of this device compared to the temperature change method. Potential commercial applications of the device are also discussed.