Packing Peanuts Attic Insulation

The very reason why plastic peanuts work well as packing makes them a bad choice for wall insulation.

Packing peanuts attic insulation.

Most packing peanuts are made of polystyrene. We found millions of packing peanuts loose in the attic presumably intended to function as insulation. If they get wet they ll dissolve and they re made to be highly biodegradable so they ll break down pretty quickly anyway. The r value of polystyrene is about 4 0 per inch.

The older kind might work okay. Osborn a former associate editor replies. Another problem is that newer environmentally friendly cornstarch peanuts dissolve when wet. I m not convinced that it s effective or even safe.

New packing peanuts are made from a type of corn starch. I m not sure when they switched to the new kind but it wasn t more than five years ago or so. Plastic peanuts hold air that helps cushion whatever is being shipped. The problem comes from the large interstitual spaces between the pieces.

Has anyone ever seen this before. 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.