Why is my Roof Hot?
Before answering this question I want to explain what the 3 ways heat is transfered to answer why you roof is hot. Heat can only be transferred by direct heat, convective, or by radiant heat and if you stop all three ways of heat even passing through your roof, then you will have a cool attic and cooler roof, and I’ll get into that later.
Direct heat is when heat passes right through, or into something, if you think about coffee, when you put hot coffee into a paper cup the heat is transferred through the paper normally where you cannot hold the paper coffee cup without the help of another paper sleeve. Now think about the times that you have hot coffee in a styrofoam cup, you can hold the cup without any sleeves, why you might ask? styrofoam does not allow the transfer of heat to pass through from the coffee to you hand, so it stops the direct head, or a good amount of it. That is the basic idea behind direct heat, and when you think about asphalt shingles, it’s not a hidden fact that they transfer heat very well.
Convective heat is the hot air heating something up. Think of the oven when you cook a chicken, its the hot air that is cooking the chicken by way of convecting the heat. When your roof is hot, and the direct heat transfers into your attic by way of your roof when the air in your attic has convective heat. In most attics that we test we find them to be 150 degrees on only a 85 degree day outside, and radiant heat play a role in this process as well.
Radiant heat is the radiant waves that come through your roof and attic that can be much hotter in temperature than the outside temperature. Think about your car in the summer months sitting in the sun with the windows up. I’ve heard some people say that inside their car it cannot be hotter than the outside air temperature, this is not true at all. Radiant heat is one of the main reasons for this. Next time you what to test this fact out go to your car while in direct sun with you windows up on a day that is 85 degrees or hotter and take a temperature reading, you will find as I did that on your dash it might be as hot as 145 degrees, that would be 60 degrees hotter than the outside air temperature. Use a windshield reflector that you can buy at the store and only open it half way across you dash. Now test the temperatures and you will find that the side without the reflector is well into the 100 degree mark, and the side with the reflector is much cooler and closer to the outside air temperature. This is a very rough test and has a lot of variables.
The three ways that radiant head are transfer are the biggest reason why your roof is hot, and without stopping those three ways that head is transferred you will be spending more money on cooling cost even with good insulation and will most likely be lowering the life expectancy of your current roof by not allowing the air to escape properly. Our Therma Vent system stops all three ways heat is transferred and changes attic temperature from 150 degrees to 103 degrees. For more information on this system which is called the most energy efficient ventilation system in America please take a look at our website AlphaRain.com.