Given the importance that enthalpic and entropic contributions have in the interplay between thermodynamics and self-assembly of aqueous amphiphile systems, the energetic characterisation of the system {water+1-propoxypropan-2-ol (1-pp-2-ol)} at T=298.15K was made by directly measuring excess partial molar enthalpies of 1-pp-2-ol and water, over the entire composition range, at T=298.15K and atmospheric pressure. Derivatives of the partial molar properties with respect to the composition are used to improve the understanding of molecular interactions in the water-rich region. The present results were compared with those for the well-studied system {water+2-butoxyethanol (nC4E1)}, the two amphiphiles being structural isomers.