In the last years the study of non local functionals have attracted great interest in view of their importance for the applications. In this talk I will present some recent results on the asymptotics of non local energies of convolution-type, imposing a Dirichlet type condition on a periodic perforation of the domain. More in detail, I will show that the interplay among the periodicity, the size of the perforations, and the approximation parameter affects deeply the asymptotic behaviour of the energies, highlighting different phenomena. The results presented in this talk have been obtained in collaboration with R. Alicandro (Napoli) and M.S. Gelli (Pisa).