A humidity meter includes a humidity sensor, a heating device oriented towards the humidity sensor, a signal generator capable of modulating a power output of the heating device, and a lock-in amplifier capable of demodulating a response signal of the humidity sensor as induced by the modulated heating device. A method of measuring humidity includes the steps of providing a humidity sensor positioned along a channel, a heating device positioned opposite the humidity sensor along the channel, and a controller including a signal generator and a lock-in amplifier; providing an airflow along the channel; modulating a power supply to the heating device using the signal generator; and demodulating a response signal of the humidity sensor induced by the modulated heating device.