Relative Luminance and Heat Reflection Formula
The visualizer converts your selected hex color to RGB and applies the WCAG relative luminance formula, L = (0.2126 x R + 0.7152 x G + 0.0722 x B) / 255, to produce a heat-reflection percentage (an SRI-style estimate) for whichever surface you are recoloring, such as walls, roof, doors, trim, garage, or fence.