1977 sells the replacement fiberglass packing. If you look on dirt bike sites you can find alternatives for packing. If you have a local power sports store you may be able to find it there. I assume you mean house insulation? It would seem to me that standard insulation would not be the best choice as it would load up faster and it would probably break down faster because its not as substantial of a material. However, I am far from an expert in such matters.