A Simple Method to Minimize Humidity Measurement Error in Psychrometers

This work demonstrates that simple calibration procedures can reduce the errors in determining relative humidity with a psychrometer by up to 75 times. The psychrometer uses two temperature transducers to measure relative humidity. The calibration consists of comparing both transducers before assembling the psychrometer. A psychrometer assembly is presented, built from readily available parts, which provides temperature data for comparison with a theoretical model. The results are compared against a reference psychrometer to assess errors with and without calibration. A twenty-two-fold decrease in error was observed for a relative humidity of 62%.