After years of research, it has been proven that reflective foil products are excellent blockers of radiant heat transfer. Although conventional mass insulation products (fiberglass, loose fill, wood, etc.) are effective against convection and conduction, they have no effect on 'radiated' heat transfer. All they do is slow it down!

A layer of radiant barrier in the center of two air spaces has two efficient reflective surfaces. This serves to protect against heat loss in the winter and heat gain in the summer. The surface facing the flow of heat will reflect 95% - 97% of the heat rays.

R-values: Are a measure of thermal resistance to heat transfer caused by conduction and convection, but do not measure a product's ability to reflect radiant heat energy.

Conduction: Fast-moving molecules on the hot side colliding with and transferring energy to slower-moving molecules on the cold side cause conduction through a solid material. Conduction heat transfer is the flow of thermal energy in matter as a result of molecular collisions. For example, if one end of a metal bar is held in a flame, heat is conducted along the bar. This conduction is initiated by the excitation, or increased vibration, of metal molecules at the hot end of the bar. The excited molecules then collide with other molecules, exciting them also. This process passes thermal energy along the length of the bar. It continues as long as a temperature difference is maintained between the two ends.

Convection: Occurs when air or fluid moves; warm air rises and cold air falls to create a convection loop. While conduction involves energy transfer on a microscopic, or atomic, scale, convective heat transfer results from the motion of large-scale quantities of matter. Convection is important in gases and liquids, which are able to expand significantly when they accept thermal energy and can develop currents of material flow. For example, convective heat transfer occurs in a pan of water being heated on a stove. The water at the bottom of the pan accepts heat energy from the pan by conduction. The water in this region then undergoes thermal expansion and is buoyed upward by the surrounding, denser water. The lighter water carries thermal energy throughout the pan by this convection process. That is, the convection current that has been established travels throughout the body of the water, transferring heat and causing a temperature redistribution. Convection currents permit buildings to be heated without the use of circulatory devices. The heated air moves solely by gravity.

Conventional mass insulation slows down the transfer of heat caused by conduction and convection, and the effectiveness of the slowing down process is measured in Hr ft2 °F/BTU (R-Value). True real life R-Vaules are difficult to determine due to the mass insulation degradation caused by condensation, compression and insulation integrity.

Radiation: From a heat source, radiation is transmitted though air or a vacuum to cold surfaces at a speed of 186,000 miles/second, but only manifests itself as heat when the rays strike an object. Conventional thermal insulation does not stop these heat rays. Radiative heat transfer involves the flow of energy in the form of electromagnetic waves. Radiation thus differs fundamentally from conduction and convection, in that it does not depend on the presence of matter. The energy of electromagnetic radiation is not the same thing as heat, but when the radiation strikes an absorbing material it is converted into heat. Heat may even be transmitted across a vacuum in this way, through conversion processes. To be transmitted, however, the energy must originate in matter at a higher temperature than the matter receiving the energy.