The other name of Radiant Barrier is reflective barriers. A thermal radiation is a mode of exchange of heat in those barrier. Heat can also be carried via convection and conduction. Theses Radiant Barrier are not capable to stop this heat transfer by any means.

Via thermal radiation, energy is released by each and every substance and the extent of which depends on surface temperature and the relative ability of the substance to emit radiation which in turn is directly proportional to heat radiated at specific wavelengths. How much energy a body reflects at a specific length is known as its reflectivity.

For those wavelengths at which the Radiant Barrier function, there emissivity is to be maintained low as much as .1 or less. The wavelength usually lies within mid and long infrared spectrum that is approximately 3 to 15 micrometers for long structures. The value of reflectivity isn't fixed for Radiant Barrier. This happens as emissivity and reflectivity never gets added to give one for varying wave length. Thus it is mandatory to have low thermal emissivity to create dark color surfaces. If radiation is not desired, the direction of the radiant surfaces must be towards open surfaces like air or vacuum.

Uses of Radiant Barrier

A substance was developed by NASA that was reflective, light and made of plastic substrate and was aluminum coated by vapor deposition technique which is commonly known as space blanket. It is used for protection of equipments, astronauts and spacecraft from radiation and even for the retention of heat as temperature fluctuations are frequent in space. As heat transfer in space is possible only through radiation therefore, Radiant Barrier are more effective and useful in space rather than on earth where the heat transfer can also be possible via convection and conduction even after deploying Radiant Barrier.

Radiant Barrier can also be deployed to bring down indoor heat loss.

Two ways through which Radiant Barrier are to be installed are as follows:

1.Radiant Barrier Decking

2.Radiant Barrier Attic Foil.

The roof of the building absorbs solar energy on sunny days and this heat is radiated downwards to the floor. By placing a radiant barrier in the attic floor the heat is reflected making the top surface cool and at the same time preventing the heat from entering the rooms. This makes a radiant barrier an efficient reflecting device.

The traditional technique of insulating an attic and a radiant barrier are different from each other. Though their use is comparable but their functioning differs as the Radiant Barrier decrease the heat radiated around them whereas the conventional method of attic insulation cuts down thermal radiation via convection. In this process the air gets trapped inside only. R-value is the scale which rates this method. Radiant Barrier has no R-values as they depend on a lot of factors.

Radiant Barrier comes in different ranges. The cost primarily depends upon the one who is installing it. There are some other functions also which individuals like to add on and the life of the house also matters as there's a difference in installation prices for old and new houses.

Therefore Radiant Barrier is very much helpful devices these days. People prefer them over other means these days.