An analytical model for heating and evaporation of a single component liquid drop is developed. The model accounts for the temperature dependence of density, diffusivity, thermal conductivity and specific heat of the gas species. The effect of variable properties on heat and evaporation rates is analysed and a comparison with the prediction of the classical constant property model is reported for six different species and different operating conditions. The model allows to evaluate the effect of the choice of the gas mixture averaging parameter (the relative weight of free stream and drop surface conditions) on the prediction of the constant property model, and a way to optimise the choice is proposed. The results can be extended to non-spherical drop and examples are reported. (C) 2019 Elsevier Ltd. All rights reserved.