A respiration humidifier having a base unit and a chamber constructed to hold liquid. A sensor is connected to the chamber and configured to sense a condition within the chamber. A radiation signal transmitter is carried by the chamber and associated with the sensor. The transmitter wirelessly sends a radiation signal indicative of the sensed condition. The humidifier includes a radiation signal receiver carried by the base unit for receiving the signal. The humidifier includes a control unit that controls the condition based on the radiation signal received by the radiation signal receiver. Another aspect provides a breathing system using the humidifier. The breathing system includes a gas flow generator that generates a flow of gas to a user circuit coupled to the gas flow generator and adapted to communicate the flow of gas to a user.
