The Q Corp Psychrometer is designed for use within an array of airflow systems in which detailed thermal tests are being conducted. Testing environments involving airflow measurement require that the focal air stream in contact with the unit under test (UUT), also pass through a flow metering device. Therefore, any air which is sampled before entering the meter device must be returned to the air stream, as an unknown amount of air being removed from the system may skew results. If air is sampled downstream of airflow meter (i.e., after the airflow across the test product has been measured), return ducting is not necessary.