eli5: If white reflects light, why do most houses have black shingles on the roof?
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Cost, durability, and appearance.
Asphalt is cheap, in order to have white shingles you’d need to use another, naturally white material that may or may not have the other properties you’d need, or to paint them white which adds $$$. You’d also need to repaint them intermittently as water exposure will gradually wear down the paint, and dark colors hide any stains/dirt/mildew/etc dramatically better than white.
>eli5: If white reflects light, why do most houses have black shingles on the roof?
To absorb light and, therefore, heat, which helps keep the house warm, saving on heating costs.
It depends on your latitude. Closer to the tropics it’s more common to have lighter colored roofs and even bright tiles. Black roofs are more common in temperate regions with lots of snow. Black means they heat up in the sun and melt off the snow or dry off after a heavy rainstorm.
The roof of a house is typically isolated from the interior spaces by the empty space in the attic and the insulation up there, so the roof can get as hot as you want without transferring too much heat into the house.
Additionally, white roofs start to look ugly pretty quickly. A flat roof with white TPO or rolled comp roof can generally hide the roof from the ground by using 12″ parapet walls around the roof. A more traditional gabled roof is going to be visible from the ground as it gets dirtier and dirtier. A darker shingle is cheaper and doesn’t show dirt nearly as quickly.
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