Heat Transfer and Radiant Barriers

Heat is transferred from one object or air mass to another in one of three ways: conduction, convection and radiation, the latter of which is one that every Tomball roofing contractor knows about because it is most apt to influence a building’s heating and cooling costs.


Conduction occurs when heat flows directly through matter; physical contact is necessary for heat to be passed in this manner.

This type of heat transfer occurs when you leave your spoon in a cup of hot coffee or tea for too long and then attempt to pick it up the now-hot spoon. In this case, the heat from the liquid made the immersed spoon hotter, and this heat then passed through the spoon to the handle. Another kitchen-based example occurs when you place a pot on a stove to heat something up as the heated burner makes the pot hotter which heats up the food that is in it.


Convection occurs when heat is transported in a liquid or gas. This is famously known by the phrase, “hot air rises,” as something adding heat to the surrounding air such as a heated stove will cause cooler air, which is heavier, to be drawn in from the sides to replace the lighter hot air, which is now heading to the ceiling.

This form of heat transfer is also what causes much of the weather we experience. For example, as warm air rises and cooler air rushes in to replace it near the earth’s surface, wind develops.


This form of heat transfer is more accurately described as the deflection of heat and the extent to which this is done. For example, foil insulation only absorbs 5 percent of the heat that it receives, bouncing back 95 percent of the heat radiation. If you hold some foil insulation next to your face, before long you will feel almost of the heat from your own body bouncing back at you from the foil insulation due to its low rate of heat absorption.

That is why something that radiates back a significant majority of the heat sent to it is great to use on roofing or the sides of a building, areas directly heated by the sun. Of course, every Tomball roofing company knows this well considering how hot the climate is here in Tomball and how much home owners and businesses pay annually in cooling costs.

Note that every object that has a temperature above absolute zero, which is -459.67 degrees Fahrenheit, emits at least some radiation in every direction until the reflected heat is absorbed by another object. The only thing that varies between objects is how much radiation is emitted.

One way this relates to roofs and attics is that roughly two-thirds to three-quarters of the heat sent from a warmer wall to one that is cooler is done by radiation. This is why the type of insulating used between the outer and inner walls of a building is so important.

Of course, the types of materials used to roof the building also have a lot to do with how much heat is radiated back off of the roof and how much is absorbed into the attic and the rest of the house.

If you are looking to get a Tomball roof replacement, contact Paramount Roofing, Inc. We will install the best radiant barrier and roofing materials to ensure that your cooling costs are as low as possible.