The Thermostat Lied (And Your Energy Bill Told the Truth)
VAV boxes provide cooling and a heating coil in harmony, with both functions controlled by a single thermostat. When the heating valve no longer seats properly, unwanted heat continuously enters the airstream. The thermostat automatically responds by increasing cooling to maintain the desired room temperature. As a result, occupants remain comfortable while energy is wasted through simultaneous heating and cooling—a problem that often goes unnoticed because the control system masks the inefficiency.