Whether you live in a warm weather climate or a climate so hot that you can fry an egg on the sidewalk, radiant barrier can provide you with huge energy saving and cooling benefits to your home. In fact, studies show some of the greatest reductions in heat transfer come from homes in warm climates with radiant barrier during the hot summer months.
To understand how radiant barrier works in warm weather climates, you first have to understand the three different types of heat making their way into your home. The three modes of heat transfer are: conduction, convection, and radiation.Conductive heat transfer happens as heat passes from one solid object to another. A good example of conductive heat in action is a cooking pot sitting on a stove. Heat conducts from the stove to the cooking pot, heating it up.
Convective heat transfer, often referred to as convection, is the transfer of heat from one place to another by the movement of fluids or gases. Convection can be seen in the common expression “hot air rises” as smoke billows out of chimney.
Radiant heat transfer is the last and most dominant mode of heat transfer. Radiant heat transfer is the transmission of electromagnetic rays through space. These rays are more commonly known as infrared rays, and the biggest source of these rays is from natures largest natural energy source, the sun.
Different types of heat transfer contribute to the flow of heat down into your home during warm weather, but radiant heat accounts for about 93%, making it by far the most dominant contributor of summer heat gain.
In warm weather, the sun’s radiant heat waves beat down on your home, travel into your attic and eventually into your home. Studies show that on a hot summers day, the roof of a home absorbs solar radiation at a higher rate than it can dissipate, meaning most of that heat will eventually reach your home. Therefore, your attic space is often 30 to 40 degrees hotter than the outside air.
Traditional forms of insulation like fiberglass, cellulose and foam only work to slow down the transfer of heat. They absorb heat much the same way that a sponge absorbs water. But just as a sponge filled with water can no longer hold any more water, with every new drop that hits it, another drips out the other side. Insulation works the same way. As it becomes saturated with heat and can’t hold anymore, it becomes ineffective. As each new BTU of heat hits it, another is transferred through to the ceiling of your home.
Radiant barrier, on the other hand, reflects the radiant heatwaves instead of absorbing them the way insulation does. Our radiant barrier products reflect 95% of radiant heatwaves. Thus, a radiant barrier can provide such big advantages to homes in warm to hot climates – they can prevent the majority of heat from ever entering the home in the first place.
Radiant Barrier research was conducted at Tennessee Valley Authority on warm climates in the summer. With an average outside temperature of 89 degrees during the day, an attic with R 19 (about 6 inches of fiberglass) and a radiant barrier outperformed R 30 (about 10 inches of fiberglass) without a radiant barrier.
By reflecting out the heat before it has a chance to be absorbed into your insulation and emitted into your home, a radiant barrier has the potential to keep your home at a comfortable temperature all summer, save 17% on your cooling costs, and make you money with continued savings every year.