The design is the visual features of the INSULATING BUILDING PANEL shown in the drawings, whether those features are features of one of shape, configuration, ornament or pattern or are a combination of any of these features. Variants are included. The broken lines composed of even length dashes and alternating long and short dashes in Figures 1, 2, 4, 8, 9, 18, 22, 23, 25, 85, 86, 88, 92, 93, and 95 represent demarcations on the INSULATING BUILDING PANEL which form part of the article.Drawings of the design are included, as follows:Figure 1 is a front perspective view of the Insulating Building Panel;Figure 2 is a front elevation view of the Insulating Building Panel of Figure 1;Figure 3 is a first side view of the Insulating Building Panel of Figure 1;Figure 4 is a back elevation view of the Insulating Building Panel of Figure 1;Figure 5 is a second side view of the Insulating Building Panel of Figure 1;Figure 6 is a top end view of the Insulating Building Panel of Figure 1;Figure 7 is a bottom end view of the Insulating Building Panel of Figure 1;Figure 8 is a front perspective view of a first variant of the Insulating Building Panel;Figure 9 is a front elevation view of the Insulating Building Panel of Figure 8;Figure 10 is a first side view of the Insulating Building Panel of Figure 8;Figure 11 is a back elevation view of the Insulating Building Panel of Figure 8;Figure 12 is a second side view of the Insulating Building Panel of Figure 8;Figure 13 is a top end view of the Insulating Building Panel of Figure 8;Figure 14 is a bottom end view of the Insulating Building Panel of Figure 8;Figure 15 is a front perspective view of a second variant of the Insulating Building Panel;Figure 16 is a front elevation view of the Insulating Building Panel of Figure 15;Figure 17 is a first side view of the Insulating Building Panel of Figure 15;Figure 18 is a back elevation view of the Insulating Building Panel of Figure 15;Figure 19 is a second side view of the Insulating Building Panel of Figure 15;Figure 20 is a top end view of the Insulating Building Panel of Figure 15;Figure 21 is a bottom end view of the Insulating Building Panel of Figure 15;Figure 22 is a front perspective view of a third variant of the Insulating Building Panel;Figure 23 is a front elevation view of the Insulating Building Panel of Figure 22;Figure 24 is a first side view of the Insulating Building Panel of Figure 22;Figure 25 is a back elevation view of the Insulating Building Panel of Figure 22;Figure 26 is a second side view of the Insulating Building Panel of Figure 22;Figure 27 is a top end view of the Insulating Building Panel of Figure 22;Figure 28 is a bottom end view of the Insulating Building Panel of Figure 22;Figure 29 is a front perspective view of a fourth variant of the Insulating Building Panel;Figure 30 is a front elevation view of the Insulating Building Panel of Figure 29;Figure 31 is a first side view of the Insulating Building Panel of Figure 29;Figure 32 is a back elevation view of the Insulating Building Panel of Figure 29;Figure 33 is a second side view of the Insulating Building Panel of Figure 29;Figure 34 is a top end view of the Insulating Building Panel of Figure 29;Figure 35 is a bottom end view of the Insulating Building Panel of Figure 29;Figure 36 is a front perspective view of a fifth variant of the Insulating Building Panel;Figure 37 is a front elevation view of the Insulating Building Panel of Figure 36;Figure 38 is a first side view of the Insulating Building Panel of Figure 36;Figure 39 is a back elevation view of the Insulating Building Panel of Figure 36;Figure 40 is a second side view of the Insulating Building Panel of Figure 36;Figure 41 is a top end view of the Insulating Building Panel of Figure 36;Figure 42 is a bottom end view of the Insulating Building Panel of Figure 36;Figure 43 is a front perspective view of a sixth variant of the Insulating Building Panel;Figure 44 is a front elevation view of the Insulating Building Panel of Figure 43;Figure 45 is a first side view of the Insulating Building Panel of Figure 43;Figure 46 is a back elevation view of the Insulating Building Panel of Figure 43;Figure 47 is a second side view of the Insulating Building Panel of Figure 43;Figure 48 is a top end view of the Insulating Building Panel of Figure 43;Figure 49 is a bottom end view of the Insulating Building Panel of Figure 43;Figure 50 is a front perspective view of a seventh variant of the Insulating Building Panel;Figure 51 is a front elevation view of the Insulating Building Panel of Figure 50;Figure 52 is a first side view of the Insulating Building Panel of Figure 50;Figure 53 is a back elevation view of the Insulating Building Panel of Figure 50;Figure 54 is a second side view of the Insulating Building Panel of Figure 50;Figure 55 is a top end view of the Insulating Building Panel of Figure 50;Figure 56 is a bottom end view of the Insulating Building Panel of Figure 50;Figure 57 is a front perspective view of an eighth variant of the Insulating Building Panel;Figure 58 is a front elevation view of the Insulating Building Panel of Figure 57;Figure 59 is a first side view of the Insulating Building Panel of Figure 57;Figure 60 is a back elevation view of the Insulating Building Panel of Figure 57;Figure 61 is a second side view of the Insulating Building Panel of Figure 57;Figure 62 is a top end view of the Insulating Building Panel of Figure 57;Figure 63 is a bottom end view of the Insulating Building Panel of Figure 57;Figure 64 is a front perspective view of a ninth variant of the Insulating Building Panel;Figure 65 is a front elevation view of the Insulating Building Panel of Figure 64;Figure 66 is a first side view of the Insulating Building Panel of Figure 64;Figure 67 is a back elevation view of the Insulating Building Panel of Figure 64;Figure 68 is a second side view of the Insulating Building Panel of Figure 64;Figure 69 is a top end view of the Insulating Building Panel of Figure 64;Figure 70 is a bottom end view of the Insulating Building Panel of Figure 64;Figure 71 is a front perspective view of a tenth variant of the Insulating Building Panel;Figure 72 is a front elevation view of the Insulating Building Panel of Figure 71;Figure 73 is a first side view of the Insulating Building Panel of Figure 71;Figure 74 is a back elevation view of the Insulating Building Panel of Figure 71;Figure 75 is a second side view of the Insulating Building Panel of Figure 71;Figure 76 is a top end view of the Insulating Building Panel of Figure 71;Figure 77 is a bottom end view of the Insulating Building Panel of Figure 71;Figure 78 is a front perspective view of an eleventh variant of the Insulating Building Panel;Figure 79 is a front elevation view of the Insulating Building Panel of Figure 78;Figure 80 is a first side view of the Insulating Building Panel of Figure 78;Figure 81 is a back elevation view of the Insulating Building Panel of Figure 78;Figure 82 is a second side view of the Insulating Building Panel of Figure 78;Figure 83 is a top end view of the Insulating Building Panel of Figure 78;Figure 84 is a bottom end view of the Insulating Building Panel of Figure 78;Figure 85 is a front perspective view of a twelfth variant of the Insulating Building Panel;Figure 86 is a front elevation view of the Insulating Building Panel of Figure 85;Figure 87 is a first side view of the Insulating Building Panel of Figure 85;Figure 88 is a back elevation view of the Insulating Building Panel of Figure 85;Figure 89 is a second side view of the Insulating Building Panel of Figure 85;Figure 90 is a top end view of the Insulating Building Panel of Figure 85;Figure 91 is a bottom end view of the Insulating Building Panel of Figure 85;Figure 92 is a front perspective view of a thirteenth variant of the Insulating Building Panel;Figure 93 is a front elevation view of the Insulating Building Panel of Figure 92;Figure 94 is a first side view of the Insulating Building Panel of Figure 92;Figure 95 is a back elevation view of the Insulating Building Panel of Figure 92;Figure 96 is a second side view of the Insulating Building Panel of Figure 92;Figure 97 is a top end view of the Insulating Building Panel of Figure 92; andFigure 98 is a bottom end view of the Insulating Building Panel of Figure 92.