Substrate provided with a stack having thermal properties

A material includes a transparent substrate coated on one face with a stack of thin layers successively including, starting from the face, an alternation of three silver-based functional metal layers denoted, starting from the substrate, first, second and third functional layers respectively Ag1, Ag2 and Ag3, and of four dielectric coatings denoted, starting from the substrate, M1, M2, M3 and M4, with optical thicknesses respectively To1, To2, To3 and To4. Each functional metal layer is positioned between two dielectric coatings. The geometrical thickness of the second functional layer Ag2 is less than the thickness of the first functional layer Ag1. The geometrical thickness of the second functional layer Ag2 is less than the thickness of the third functional layer Ag3. The dielectric coating M2 exhibits a lower optical thickness To2 than the optical thicknesses To1, To3 and To4 respectively of the dielectric coatings M1, M3 and M4.