Substrate provided with a stack having thermal properties

A transparent substrate comprising a stack of layers successively including from the substrate an alternation of at least first, second and third functional metal layers, and of at least first, second, third and fourth antireflective coatings, so that each functional metal layer is arranged between two antireflective coatings, each antireflective coating comprising at least one dielectric layer, wherein:

• thicknesses of the first, second and third functional metal layers starting from the substrate increase as a function of a distance from the substrate,
• the stack comprises:
• at least one absorbent layer in the first antireflective coating, or a blocking underlayer directly in contact with the first functional metal layer,
• a ratio of a physical thickness of the second functional metal layer to a physical thickness of the first functional metal layer being between 1.35 and 1.90, inclusive,
• the third functional metal layer has a physical thickness between 17.5 and 24.0 nm,
• wherein a ratio of an optical thickness of the first antireflective coating to an optical thickness of the second antireflective coating is below 0.8,
• wherein the transparent substrate has a visible light transmission between 55 and 62%, an external reflectance values (RLext) of less than 14% and an internal reflectance (RLInt) of less than 17%.