In the meat industry investment and running costs for chillers are determined mainly by the chilling time and the weight losses associated with chilling or storage. The aim of this study was to assess the consequences of the spatial heterogeneity of air-flow properties in rooms and to optimise the multi-stage low air temperature chilling process used to reduce weight losses. The calculations which provide the chilling kinetics of either pork carcasses or cylinders were performed using a mathematical model which had already been tested, and with air/product transfer coefficients which had been measured independently for various air velocities and turbulence intensities. The results show the relative effect of product thickness and air-flow properties under practical conditions and indicate the limits of low air temperature chilling tunnels. They also suggest that if a homogeneous low velocity, low turbulence intensity air flow could be controlled in chillers, then the air temperature could be very low thus reducing weight losses dramatically.