We are AlphaRain.com @ (540) 222-1642. We didn’t know the true answer so we conducted an experiment. We recently installed a roof that had soffit vents but not a lot of ridge vent. There was about 25% of the total ridge that was vented and then there were two gable vents at either end of the main gabled roof.
We took the attic air temperature on a sunny 88 degree day at 2 PM. In the middle of the attic at the peak it was 150 degrees. At either end close to the gable vents at the peak it was 129 degrees.
We then installed the roof in such a way that as air escaped through the full length vented ridge vent cooler air was drawn in through our unique vented eave vent.
Here are the results:
Date: Saturday 9/6/14
Time Outside Temp Attic Temp
12 noon 86 100
1 PM 89 105
2 PM 90 114
3 PM 90 114
4 PM 86 112
5 PM 83 104
As you can see by only ventilating the attic properly we reduced the attic air temperature by 36 degrees.
Keep in mind the standing seam metal roof was not a light colored standing seam metal roof but an Antique Black color.
Watch this video to see how to reduce it to 103 degrees.
For more information please visit our website, AlphaRain.Com or call us @ 540-222-1642 for pricing information