A flow generator and humidifier construction is described, including a flow generator construction adapted to reduce noise output compared to known flow generators of comparable size. The flow generator includes a chassis forming first and second muffler volumes and a venturi-shaped connection portion, and a metal/polymer composite material blower enclosure which suppresses noise from the blower. The flow generator is programmed to include a promoting system which has a list by which the user asks for specified actions such as part replacing, doctor calling and/or data card entering of patients and etc.