Radiant Barrier

All That You Ever Wanted to Know! 

What is a radiant barrier?

It is a material usually installed in buildings in order to minimized summer heat as well as loss of winter heat. The basic idea of installing a radiant barrier is to reduce heating of a particular building as well as cooling energy utilization.

The basic advantage of installing an attic radiant barrier is to minimize the loads of air conditioning cooling in both hot and warm climates. This device comes with a thin sheet or a covering of reflective material such as aluminum. The covering is applied to either one or both sides of substrate material. The material may include the following mentioned below:

·        Kraft paper

·        Plastic films

·        Card board

·        Plywood sheathing

·        Air infiltration barrier material

Some of the products mentioned above are also fiber reinforced to maximize the durability and easy handling. A radiant barrier can be easily used in all types of commercial, residential and industrial buildings.

Radiant barrier installation:

When it comes to installing a radiant barrier in residential attic, the installation can be carried out in varied configuration. The easiest way to install is to lay it on the attic insulation in conjunction with reflective side up.

Another option is to install a radiant barrier is to attach it adjacent to roof. There are several variations on roof application. First variation is to add the barrier to the attic truss chord’s bottom part or even the rafter framing. There is another option to drape the barrier on rafter tops just prior to the application of the roof deck. You can even opt for attaching it directly towards the underside of the roof deck.

The functioning:   

A radiant barrier functions via minimizing transfer of heat through thermal radiation across the air space that exists between the attic floor and roof deck. This is also the space where insulation is traditionally placed.

Almost all materials tend to emit thermal energy radiation due to the temperature they experience. The energy that is exactly emitted depends on the temperature of the surface as well as emissivity. Emissivity is a property and defined as a number that exists anywhere between zero and one. The amount of emissivity increases with the increase in this number.

Another property closely associated with emissivity is reflectivity. It is the measurement of the amount of radiant heat that any material reflects. The reflectivity can also be refined to as a number existing between zero and one. Any opaque material gives out the sum one when the reflectivity and emissivity are added. Now, this indicates that any material with high reflectivity tends to show low emissivity and a material with low reflectivity will show high emissivity.

Radiant barrier materials need to possess higher amount of reflectivity. This usually amount to anywhere between 0.9 to 90 percent or even more where as a radiant barrier with low emissivity needs to measure about 0.1 or even less. It is every important for a it to face an open air space in order to function well.

Radiant barrier can also be effective in minimizing energy that is radiated from the insulation of the top surface.

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