Spandrel Panel Calculator

Opaque panel insulation and finish for spandrel areas.

Panel width (mm)

Panel height (mm)

Target R-value (m²·K/W)

Insulation type (1-3)

Spandrel glass (mm)

Temperature swing (°C)

Tab to move between fields

Insulation thickness (mm)

100

Spandrel U-value (W/m²·K)

0.2

Actual R-value (m²·K/W)4.55

Total build-up depth (mm)133

Glass thermal expansion (mm)1.08

Total panel weight (kg)39.7

Glass weight (kg)27

Insulation weight (kg)5.4

Insulation NamePolyiso

How to Use This Calculator

Enter the spandrel panel width and height in millimeters.
Set the framing system (stick-built or unitized) and thermal insulation R-value.
Input the panel weight for structural dead load calculations.
Review the overall spandrel U-value and estimated annual heat loss.
Use the panel weight to specify anchor design loads in structural drawings.

How the result changes with Target R-value (m²·K/W)

Panel width (mm): Width of the spandrel panel module.
Panel height (mm): Height of the spandrel zone (floor slab depth + fire-safing).
Target R-value (m²·K/W): Required insulation R-value per energy code (ASHRAE 90.1). Typical: R-3.0 to R-4.5.
Insulation type (1-3): 1 = Mineral wool, 2 = Polyisocyanurate, 3 = Extruded polystyrene (XPS).
Spandrel glass (mm): Thickness of opacified spandrel glass (ceramic frit or painted back).
Temperature swing (°C): Total temperature range the spandrel glass experiences (dark colors can reach 80–100°C swing).

Insulation thickness (mm): Required insulation thickness rounded up to standard 25 mm increments.
Actual R-value (m²·K/W): Achieved R-value with standardized insulation thickness.
Spandrel U-value (W/m²·K): Overall spandrel panel U-value including all layers and air films.
Total build-up depth (mm): Total depth from outside face of glass to inside face of back pan.
Glass thermal expansion (mm): Maximum thermal expansion of spandrel glass across the temperature swing.
Total panel weight (kg): Combined weight of glass, insulation, and aluminum back pan.
Glass weight (kg): Weight of the spandrel glass alone.
Insulation weight (kg): Weight of the insulation layer.

Identify Input Parameters
4 parameters
Panel width (mm) = 1500, Panel height (mm) = 1200, Target R-value (m²·K/W) = 3.5, Insulation type (1-3) = 2 = 6 input(s) provided
Calculate Insulation thickness
Insulation thickness = ceil(insulThickMm / 25) * 25
100 = 100
Calculate Spandrel U-value
Spandrel U-value = 1 / rTotal
0.204 = 0.204
Calculate Actual R-value
Actual R-value = (standardThickMm / 1000) / conductivity
4.55 = 4.55
Calculate Total build-up depth
Total build-up depth = glassThickness + shadowBoxDepth + standardThickMm + 1.5
133 = 133