I have reproduced below an article from the construction professional publication Solplan Review November 2008 because it was such a good article on this complicated subject. In 2023, Solplan Review is no longer in publication. For an animation on what is a rainscreen, follow this link.
But...
Example: Styrofoam products by Dow (by the way, Styrofoam is a Dow Chemical brand name and not a generic term for foam insulation).
Colour: Blue (Dow) or Pink (Celfort)
Thermal Resistance: RSI - .035/mm R - 5.0/in. Very high.
Cost: high
Capacity to dry out if wet: Won't get wet
Fire Resistan...
