Although surfactant detergency is well understood above 30 C, actions of surfactants below 30 C are not well established. In the era of energy saving and environment caring, we must understand how to optimise detergency in what are increasingly hostile environments. Existing surfactant mixing theories such as regular solution theory are not validated at low temperatures, and other factors such as being closer to the solubility limit of the surfactants, and perhaps proximate to phase boundaries also need to be taken into account. It is hence vital that industry is supported with both data and a thermodynamic description of the behaviour of detergent components at ambient and below ambient temperatures. This work proposes to study how model surfactants behave in model binary mixtures below ambient temperatures on the surface of water.