The calculation of interfacial properties, such as the surface tension, from the density functional theory suffers from the overestimation of the critical temperature of all classical Helmholtz energy functionals. A Helmholtz energy functional is here proposed, where the long-range density fluctuations leading to the universal critical scaling behavior are accounted for using a renormalization group theory. The appeal of the approach is its simple implementation, where the renormalization is treated in a local density approximation (LDA). The model is almost exact at the critical point. Away from the critical point, the model reduces to the perturbed chain statistical associated fluid theory (PC-SAFE) equation of state. The conventional PC-SAFT pure component parameters are supplemented with a single substancespecific renormalization parameter, which is adjusted to reproduce the bulk phase critical temperature. The surface tension is obtained with excellent agreement to experimental data for some non-polar and moderately polar substances (alkanes, ethers, acetates and aromatic substances) up to the critical point. (C) 2010 Elsevier B.V. All rights reserved.