But when sunlight falls on a dark roof most of the light is absorbed and re radiated as much longer wavelengths which are absorbed by the atmosphere.
White roof summer dark roof winter.
Winter days are much shorter than summer days so the benefits of having black shingles wouldn t last for very long.
When sunlight falls on a white roof much of it is reflected and passes back through the atmosphere into space.
In the wintertime that can be a good thing.
Dark roofs may have a small snow melt effect but not a sizeable one.
The sun is lower in the winter which means your roof isn t getting the direct sunlight it gets in the summers which means that even with black shingles you wouldn t be absorbing that much heat.
But in summertime it s definitely a bad thing.
Your house gets even hotter and.
Similarly if your roof experiences winter problems like ice dams your roof color probably isn t the primary culprit.
A study in adelaide australia found that besides delivering cooling in summer they also act as an insulating layer to keep buildings warmer in winter.
A dark roof heats up in the sun and helps reduce your heating bill.
There is a third option competing for roof space to take the heat out of cities covering them in photovoltaic cells.
The white powder actually reflects away much of the sunlight so the dark roof underneath cannot absorb heat and melt the snow.