The invention relates to a transparent substrate, more particularly of glass and having multiple thin layers on which are successively deposited; i) a first dielectric material layer, ii) a first layer having infrared reflection properties, particularly based on metal, iii) a second dielectric material layer, iv) a second layer having infrared reflection properties, particularly based on metal, v) a third dielectric material year, characterized in that the thickness of the first layer having infrared reflection properties corresponding to about 50 to 80%, particularly 55 to 75% and preferably 60 to 70% of that of the second layer having infrared reflection properties.