Packing Peanuts Attic Insulation

Most packing peanuts are made of polystyrene.
Packing peanuts attic insulation. But the problem with using packing peanuts for attic insulation is that while the individual peanuts may have an r value of about 4 0 per inch the peanuts have large air spaces between them which allows air currents to easily flow through a layer of packing peanuts. The very reason why plastic peanuts work well as packing makes them a bad choice for wall insulation. In a wall cavity they would offer little resistance to air movement so they would be of limited r value. Good insulation works by trapping air.
The problem comes from the large interstitual spaces between the pieces. I m not sure when they switched to the new kind but it wasn t more than five years ago or so. Air with very small temperature gradients will start to float through the peanut pack and transfer heat from the warm surface to colder zones with little resistance. We found millions of packing peanuts loose in the attic presumably intended to function as insulation.
I m not convinced that it s effective or even safe. New packing peanuts are made from a type of corn starch. Osborn a former associate editor replies. The r value of polystyrene is about 4 0 per inch.
Has anyone ever seen this before. Plastic peanuts hold air that helps cushion whatever is being shipped.