The invention relates to a variable flow mixing valve for use in a Heating Ventilation and Air Conditioning module. The module is particularly suited for use in a vehicle. The variable flow mixing valve includes drive means which drive a mixing door and a baffle between various positions in order to allow a relatively warm flow of air, from a first chamber, to mix with a relatively cool flow of air from a second chamber. The baffle and door are linked in such a way as to provide an aperture therebetween through which, in use, the first and/or second flows of air pass. A parking area is also provided for the baffle and is shaped in order to reflect airflow back toward the first and second chambers.