In order to understand radiant barrier technology, it is important to review what makes you hot or cold, and how it happens in nature. The proper term to use is ENERGY TRANSFER.
There are only three modes of energy transfer: CONDUCTION, CONVECTION, RADIATION.
CONDUCTION is direct heat flow through matter, such as the conduction of heat from the hot surface of a stove to a cooking pot.
CONVECTION is the transport of heat within a gas or liquid caused by the actual flow of the material itself, such as heat traveling upward with the natural upward movement of air.
RADIATION is the transmission of electromagnetic rays through space. These rays have no temperature, only energy. Every material or object with a temperature above absolute zero emits these rays in all directions, in a straight line, until they are deflected or absorbed.