What can be a environmentally-friendly alternative to bubblewrap as cheap, semitransparent, temporary window insulation?
From your link above: “Bubblewrap as window insulation is fantastic” To be clear, it’s the air trapped between your window and the plastic that is the insulator. This means that almost anything that can hold the air in the gap will work to a degree. On your environmental point: outside of plastic, your options are: a) any other (semi)impervious membrane over the opening to create that air barrier. b) replacing the windows with double glazed units (which have two panes of glass with an air gap to help insulate) also, expensive Plastic is your best bet for a temporary fix, or a thick rug if you’re in a bind. If you’re worried about the environmental impact of plastic wrap, there’s nothing stopping you from re-using the plastic again next year, or for another project…