The Wang-Landau Monte Carlo algorithm, implemented within an effective Hamiltonian approach, is used to investigate the effect of mechanical and electrical boundary conditions on electrocaloric (EC) properties in (Ba0.50Sr0.50)TiO3 thin films. The results indicate that the EC response maximizes near the paraelectric-to-ferroelectric (respectively, ferroelectric-to-ferroelectric) phase transition is suppressed (respectively, enhanced) by activating the depolarizing field inside the films. On the other hand, the EC response shows strong dependence on both the compressive and tensile strains. Interestingly, (Ba0.50Sr0.50)TiO3 thin films are expected to show a giant EC effect near room temperature when the applied tensile strain is properly controlled. Our predictions also reveal that all observed phase transitions in the BST films are of second order and lead to an enhancement of refrigerant efficiency. (C) 2017 Elsevier Ltd. All rights reserved.