A respiration humidifier with a base unit (2), at least one sensor (3), which is connected to the base unit (2), and a mixing chamber (4), which is designed as a mixing chamber detachable from the base unit (2), with a gas-carrying area (5), wherein the mixing chamber (4) has at least one opening (6), through which the at least one sensor (3) is in connection with the gas-carrying area (5).