Experimental excess enthalpy data are reported for mixtures of n-heptane with five pentanol isomers: 1-pentanol, 2-pentanol, 3-methyl-1-butanol, 3-methyl-2-butanol and 2-methyl-2-butanol. The data were obtained using isothermal flow calorimetry and are compared with previous studies. These new data are represented by a model that combines the physical interactions of the Scatchard-Hildebrand regular solutions model with classical hydrogen bonding of the Kretschmer-Wiebe model. The model includes an adjustable parameter that reflects physical interactions and a self-association equilibrium constant that represents hydrogen bonding. (C) 2003 Elsevier Science B.V. All rights reserved.