This work investigates the heat delivered by a mono-layer 1D grating of gold nanoparticles (GNPs) created by photo-reduction through two-photon direct laser writing (2P-DLW) in a poly-vinyl alcohol (PVA) matrix doped with HAuCl4, under resonant laser radiation. We drop cast a film of a PVA + HAuCl4 mixture onto a glass substrate, in which we create gratings of 1 mm2 made by stripes of GNPs characterized by high polydispersivity. We demonstrate that, by controlling the pitch of the GNP stripes, we obtain different values of the photo-induced temperature variations. In the framework of thermo-plasmonics, the experimental investigation of the heat generation from a monolayer of gold nanoparticles represents a key element as a starting point to design thermo-smart platforms for sensing, solar energy harvesting and thermo-catalysis.