R-value vs. E-value

There are three ways that heat can be transferred in and out of your home:
R-value measures only the resistance to conduction and convection, but almost all of the energy lost in your home is through emission – radiant heat transfer. "E-value" (the ability to prevent radiant heat transfer) is far more important than R-value in evaluating an insulation system. The eShield™ Attic Energy Barrier has a much higher E-value than any form of mass insulation.

CONDUCTION heat transfer through contact between solid objects	CONVECTION air circulates and passes heat from one object to another	EMISSION direct transfer from a radiant heat source like the sun

Although you may hear a lot about the R-value of insulation, this is not the only number you need to consider when outfitting an attic, wall, or any other area of your home. In addition to allowing for heat transfer by convection and conduction, you must also take radiant heat transfer, or emission, into account. An insulation value for emission, which is the transfer of heat energy via empty space, rather than by direct contact or circulating air, is known as an E-value. It is also the main way that homes lose energy. Although they protect against convection and conduction, traditional insulation materials simply do not provide sufficient resistance to emission, leaving you open to increased energy bills and decreased comfort.

Before eShield™	After eShield™

Unlike fiberglass, cellulose, foam, or other types of insulation, eShield™ is specifically designed to protect your home from radiant heat transfer, and its E-value is unmatched. By combining traditional insulation such as fiberglass with eShield™, you can provide for all three types of heat transfer, lowering your energy consumption and therefore your power bill.