I swapped from 4.5kg butane (blue) to 3.9kg propane (orange) during the shortage because I could still get propane from the local hire shop. It is used by tradesmen for gas burners. If the supply dries up again I'll start refilling my own from bigger bottles.
If you've got a half decent sewing machine it's one of the easier jobs to replace a window using the method stated by Jaybee. I've done a couple over the years.