Heat Reduction 

When your roof absorbs radiant heat from the sun it heats up, and eventually about half of the heat will transfer into the attic. The radiant barrier consists of a highly reflective material that reflects radiant heat rather than absorbs it, thereby significantly minimizing the heat that makes its way into the attic. Attic insulation helps reduce the transferring of heat from the attic into the living space. So the Radiant barrier job is to reflect the heat so that it doesn’t even build up in the attic in the first place. Essentially, the radiant barrier is the first line of defense against heat, and attic insulation is the second. Needless to say, the radiant barrier doesn’t replace the need for insulation, as they work together in helping maintain cool temperatures in the summer, and the insulation is on its own when it comes to protecting you in the winter. While insulation is great for regulating the temperatures in the living space, radiant barrier is the only thing that shields the attic space from the terrible heat so when you, or an electrician, or someone like me (!) go up there, nobody has to suffer.