Quote:
Originally Posted by bakon
So I rode around with wife yesterday checking friends garages and attics. I measured the temps with a Harbor Freight laser gun. I have used same gun on engines and windows, it works pretty fast and finds variations inches apart on materials.
The results are open to interpretation….different size houses, different colors, different facing, one had two small Solar guys attic fans plus a garage fan venting into attic running. One had only one large Solar guy fan. Some had no extra vents. All were in Monarch Grove so about 2 1/2 to 3 years old. All were designer series with 2, 2 1/2, 3 and a 4 car garage.
Readings were around noon before the clouds rolled in. And the houses measured exactly the same, some plus or minus 2-3 degrees. None measured same temp in garage and attic. Meaning the roof was still heating the area above garage ceiling over the outside temp- vents, fans or steps left open if didn’t matter.
ALL WERE THE SAME
We can assume the soffits were in similar condition being built same time.
Garage walls and objects in garage. 88
Wood roof not near running fans 137
Wood support trusses a few feet down from roof 118
Plastic bins on attic floor 105
It didn’t matter what vents, what house, which way It faced or if stuffed full attic or empty space. The differences were less than 3 degrees.
I was hoping to see a 5-10 degree difference. Especially one house which runs two fans and a garage ceiling fan blowing in. Air has to be moving more in those over mine with nothing yet (by the way Solar guys said at minimum I need one large and one small, Have appointment next Monday and said give me two large to move more air) Not sure I am going to continue with appointment. Love to come measure the last poster’s attic compared to mine today as I am walking distance away. Have to give a call.
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So you need to be taking the
Air temperature and not the temperature of the structures. The sign that the fans are working is your 105 degree reading of the bins on the floor of the attic. If they are at 105 degrees that means the air in the attic space where you measured is about 10 degrees higher than the outside air which is what you want. The structure temperature will not vary much because there isn't enough air flow with a significant temperature difference to cool it down.
But you are correct depending on the size of your home and it's position to the sun all day long will effect how hot your attic gets.