How Radiant Barriers Work
A radiant barrier reflects or blocks radiant heat energy instead of trying to absorb it. A radiant barrier can also reduce convective heat transfer by acting as a physical blockade against convective air flow.
How does a radiant barrier reflect/BLOCK radiant heat?
The reflective surface of radiant barriers has two properties that enable it to reflect or block radiant heat when at least one air space is provided on one side:
A Radiant barrier reflects radiant heat that strikes its surface across an air space from a heat source and conversely, it emits very little radiant heat from its surface across an air space opposite a heat source.