posted 7 years ago
Aluminum is one of the more valuable and recyclable items in the waste stream. So much so that it's not even really waste if it has been segregated out of other waste. Whereas most types of "recyclable" plastic are not easy to recycle into anything worth the trouble of segregating and transporting them, so if you could recycle some plastic into insulation, that would be doing a more helpful job on the waste stream, and plastic is a much better insulater of heat than aluminum is.
The problem with plastic, though, is that it is flammable and in the event of a fire, the fumes may make the fire that much more dangerous. I don't know if the smoke would make people unconscious and unable to escape, or do immediate damage to their lungs, but it surely would be a long term damage, so we have not used plastic waste insulation in any of our living or working spaces. We used waste plastic as insulation only in two places: in the north wall of building, sandwiched in a 6-inch gap between a structural 2-foot thick rammed earth wall and a 6-inch thick jacket wall. I think it helped insulate the thermal mass of the thick inner wall, but then there was a flash flood event and the jacket wall got soaked so we removed it. The other place we used it is in the ceiling of our water tank room, where nobody will ever sleep and be caught unawares in the unlikely event of a fire in there. We didn't run any wires in the ceiling under the insulation.
Works at a residential alternative high school in the Himalayas SECMOL.org . "Back home" is Cape Cod, E Coast USA.