Has anyone ever seen this before.
Packing peanuts attic insulation.
I m not convinced that it s effective or even safe.
The older kind might work okay.
Most packing peanuts are made of polystyrene.
We found millions of packing peanuts loose in the attic presumably intended to function as insulation.
The r value of polystyrene is about 4 0 per inch.
I m not sure when they switched to the new kind but it wasn t more than five years ago or so.
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.
If they get wet they ll dissolve and they re made to be highly biodegradable so they ll break down pretty quickly anyway.
Good insulation works by trapping air.
Osborn a former associate editor replies.
Plastic peanuts hold air that helps cushion whatever is being shipped.
The very reason why plastic peanuts work well as packing makes them a bad choice for wall insulation.
The problem comes from the large interstitual spaces between the pieces.
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.