A breathing assistance apparatus comprising:a gas delivery device adapted to provide gas at a substantially positive mean pressure；a humidifier adapted to humidify said gas；wherein said apparatus is configurable to at least two configurations, a first configuration with a predetermined functionality inoperable and said gas delivery device operable, and a second configuration with said predetermined functionality operable and said gas delivery device operable,wherein the predetermined functionality is active humidification, in the first configuration said humidifier is inoperable and said gas delivery device is operable, and in the second configuration said humidifier is operable and said gas delivery device operable, andwherein a portion of said apparatus is separable from the apparatus corresponding to the first configuration, and integration of the portion with the apparatus corresponds with the second configuration.
