An analytical model of the process of paper drying has been developed in terms of the intermittent heat and mass transfer processes that occur as the sheet passes into thermal contact with the heated drying rolls and through the intervening ventilated air spaces. The model is based on a range of established paper properties, such as porosity, conductivity and diffusivity. These have been validated on the basis of wind tunnel sheet drying tests and by comparison with overall machine performance. The model is applied to the influence of operating properties, such as paper weight, on paper drying machine performance. In particular, steam consumption and machine operating speed are considered.