What Is Radiant Heat Gain?
And why is my House So HOT?
It all starts with the Attic. Have you ever gone into your attic on a hot Dallas-Ft. Worth Summer day? Did you know that the attic temperature in most homes can reach 140-160 degrees? Ideally, there would be no difference between the OUTSIDE air temperature and the air temperature INSIDE your attic. What causes your attic to be so hot? Two things: RADIANT HEAT GAIN and Inadequate or IMPROPER VENTILATION.
Heat ALWAYS moves from warmer to cooler environments. This is Newtons 2nd law of thermodynamics. Therefore, during the summer the big problem is really the HOT GETTING IN and not THE COLD GETTING OUT. This is our specialty to BLOCK THE HEAT from entering your living space.
The sun produces radiant heat. Radiant heat moves in a straight line until it is either absorbed or reflected (similar to light).
As the sun heats your roof, it starts to warm up. Eventually, the roof will get so hot it will start to RADIATE heat in all directions. Part of this heat transfer is into the attic and eventually EVERYTHING GETS HOT – the wood rafters, anything stored in the attic, (boxes, Christmas stuff, etc.), your A/C unit, all the ductwork, and finally the actual insulation inside your attic will heat up.
Think of your attic being similar to the oven in your kitchen. You turn it on and are eventually going to feel the heat outside the door. Just like an oven, the heat from the attic will eventually find it’s way into the living space. You may not notice the heat or feel uncomfortable, since your Air Conditioner can “keep up” with demand. However, with less heat entering the home wouldn’t your A/C unit run less? This would Save You Money!!
In fact, even after the sun goes down, the heat in you attic continues to radiant into your living space. It is usually 2:00-3:00am before the attic actually cools down to the outside temperature (some houses NEVER Cool down). Your A/C is fighting the heat gain the whole time. Then, when the sun comes up, the process starts over again.