Radiant barriers perform function which is similar to that of conventional insulation. Both are used to minimize heat transfer but both differ in the way they reduce the heat transfer. A radiant barrier reduces the amount of heat transferred in air that is adjacent to the radiant barrier. The primary function of conventional insulation is to trap air within the insulation there by reducing the heat transfer by air movement. The insulation fibers or particles also block radiation heat transfer through the space occupied by the insulation. Conventional insulations are generally rated by their R-value but as the effectiveness of radiant barriers depends on many variables, simple R-value ratings have not been developed yet. Costs of an attic radiant barrier and conventional insulation also differ which is base on several deciding factors.
Radiant barriers work on principle of reduction of heat loss due to thermal radiation. All materials give off, or emit, energy by thermal radiation and the amount of energy emitted depends on the surface temperature. In homes, this heat loss generally occurs between the roof deck and the attic floor. During day time solar energy is absorbed by the roof, heating the roof and causing the underside of the roof sheathing and the roof framing to radiate heat toward the attic floor. Radiant barriers is placed on the attic floor and it reflects most of the heat radiated from the hot roof back toward the roof making upper surface of insulation cooler than it would have been without a radiant barrier. This minimizes the heat transfer to the room below the ceiling. A radiant barrier also reduces heat losses through the ceiling in winters. Thus a radiant barrier effectively reduces heat transfer from within and outside of building.
Radiant barriers or reflective barriers inhibit summer heat gain and winter heat losses due to thermal radiation and hence to reduce building heating and cooling energy usage. All materials give off, or emit, energy by thermal radiation as a due to difference in temperature. The amount of energy radiated depends on the surface temperature and a property of materials. To stop this heat transfer radian barriers are used. Radiant barriers usually consist of a thin sheet or coating of a highly reflective material, usually a sheet of metallic foils alone or attached to something such as plywood or rigid foam. Radiant barriers can be used in residential, commercial, and industrial buildings.
All radiant barriers should have at least one low emissivity surface. Emissivity is expressed in value range of 0 – 1 in comparison to an opaque material, which has no reflectivity. A foil barrier panel should have an approximate value of 0.9, or a reflectivity of 90 percent at the wavelengths at which they are expected to function. Special care should be taken when installing radiant barriers to ensure that at least one reflective side of the product is installed next to an air space that will not (over time) be covered with dust. If it becomes covered with dust, such as on the floor of an attic, performance will degrade.
Radiant barriers are a great way to provide energy savings, and improve the comfort level of your home. The cost of installation varies from manufacturer to manufacturer, and from locale to locale. We at Star Spray Foam Systems, LLC offer radiant barrier insulation systems that reflect radiant heat energy instead of trying to absorb it. A pure aluminum radiant barrier reflective insulation remains unaffected by humidity and other weather conditions and continues to perform at a consistent level to maintain healthy inner environment.