A multichamber gas-filled insulated glass unit , comprising: an outer pane having a solar direct transmittance τ e,outer according to EN 410:2011 and a solar direct absorptance α e,outer according to EN 410:2011, an inner pane , at least three chambers (3, 3.1) arranged between said outer pane and inner pane, wherein adjacent chambers are divided by intermediate panes (4, 4.1), wherein the two intermediate panes closest to said outer pane have an average value av(α e,inter ) of the solar direct absorptance α e,inter according to EN 410:2011, wherein said chambers comprise a group of sealed chambers , wherein said group of sealed chambers as a whole is hermetically sealed, and each of said chambers among said group of sealed chambers is filled with an insulating gas having a thermal conductivity of λ, characterised in that the values for τ e,outer α e,outer , av(α e,inter ) and the total number N of outer, inner and intermediate panes (1, 2, 4, 4.1) are chosen such that a parameter T, which is defined as: T = 106 ⋅ α e , outer 0.07 ⋅ τ e , outer 0.32 ⋅ av α e , inter 0.32 ⋅ N 1 + λ − λ ar λ kr − λ ar ⋅ 0.4 0.466 obeys T < 80, wherein λ ar . is the thermal conductivity of a mixture of 90% argon and 10% air, and λ kr is the thermal conductivity of a mixture of 95% krypton and 5% air, wherein the values for λ, N and the corrected emissivity ε of said panes are chosen such that the EN 673:2011 U-value is less than 0.5 W/(m 2 · K), wherein the solar direct transmittance τ e,outer of the outer pane is 0.5 or less and/or wherein said outer pane is equipped with a system for dynamically changing the value of τ e,outer , said system allowing for reducing the value of τ e,outer to 0.6 or below, and wherein av(α e,inter ) is 0.15 or less. an outer pane having a solar direct transmittance τ e,outer according to EN 410:2011 and a solar direct absorptance α e,outer according to EN 410:2011, an inner pane , at least three chambers (3, 3.1) arranged between said outer pane and inner pane, wherein adjacent chambers are divided by intermediate panes (4, 4.1), wherein the two intermediate panes closest to said outer pane have an average value av(α e,inter ) of the solar direct absorptance α e,inter according to EN 410:2011, wherein said chambers comprise a group of sealed chambers , wherein said group of sealed chambers as a whole is hermetically sealed, and each of said chambers among said group of sealed chambers is filled with an insulating gas having a thermal conductivity of λ, characterised in that the values for τ e,outer α e,outer , av(α e,inter ) and the total number N of outer, inner and intermediate panes (1, 2, 4, 4.1) are chosen such that a parameter T, which is defined as: T = 106 ⋅ α e , outer 0.07 ⋅ τ e , outer 0.32 ⋅ av α e , inter 0.32 ⋅ N 1 + λ − λ ar λ kr − λ ar ⋅ 0.4 0.466 obeys T < 80, wherein λ ar . is the thermal conductivity of a mixture of 90% argon and 10% air, and λ kr is the thermal conductivity of a mixture of 95% krypton and 5% air, wherein the values for λ, N and the corrected emissivity ε of said panes are chosen such that the EN 673:2011 U-value is less than 0.5 W/(m 2 · K), wherein the solar direct transmittance τ e,outer of the outer pane is 0.5 or less and/or wherein said outer pane is equipped with a system for dynamically changing the value of τ e,outer , said system allowing for reducing the value of τ e,outer to 0.6 or below, and wherein av(α e,inter ) is 0.15 or less. <EOS>