The fact is ventilation doesn t do much.
How much will a dark shingle heat up an attic.
As you ve probably heard from many the color of your roof does affect how much heat is absorbed into your attic.
For most recorded locations the black shingled roofs were generally 10 f to 15 f warmer than identical white shingled roofs on sunny days.
But everyone agrees that dark shingles are hot shingles.
This is a fact so when heat builds up in the rooms below this heat will rise to your attic where it will become trapped.
The roofing material also affects how reflective your roof is.
However except for reflective coated shingles some energy star rated shingles for instance or white or bare metal there is only about a 10 15 difference in the amount of energy absorbed between black and say a tan or beige and only a few percent between black and a gray red dark blue green or brown.
Your attic can become super heated in ways that have little to do with your roof.
Interestingly enough during the evening the darker shingled roofs tend to lose heat faster than lighter shingled roofs.
The data on the fact that shingle color matters much more than ventilation when it comes to shingle temperatures is much more established than the data on whether hot shingles have a shorter life than cool shingles.
They found that dark shingles are 27 hotter than white shingles.
However when you get into the grays browns and tans there is only a 2 3 degree difference.
Yes black will be hotter.
When comparing a totally white shingle to a totally black shingle the attic temperature may increase 8 10 degrees.
A study by the united states department of agriculture found that wood roofing panels under black shingles were ten to fifteen degrees warmer than the same panels under white shingles on a sunny day.
When attic areas are poorly ventilated excessive heat can cause blisters to form especially on newer roofs.
Also an 8 degree increase in attic temperature does not mean an 8 degree increase in your house.
There it radiates down into the attic heating up the insulation the framing the ductwork and the boxes of christmas tree ornaments.
Or course color isn t the only aspect of your roof that affects home temperature.
A radiant barrier can help by reducing the amount of that heat that radiates downward.
If your home has an attic or overhead crawl space heat rising up from below can cause blisters and cracks in asphalt roofing shingles.
A federal study has shown that the plywood under dark roofs in direct sunlight is consistently 10 to 15 f hotter than the plywood boards under light colored roofs.
Darker colored shingles on the other hand such as charcoal will absorb much of that heat causing the temperature in your attic to rise.
So your shingles are going to get overheated and possibly even deteriorate faster no matter what the color of your roof is.
In general lighter colored roofs reflect away heat rays from the sun but dark colored roofs absorb much of that heat and transfer it into the rooms below.
