yep that they are however each has a specific insulation value. pumice being the lowest and perlite being the highest. in order to get the insulation values you have to use more materials. so you end up spending just as much to get 4 times the pumice as you would for a two 2 cubic foot of perlite.
Need more info?
Ernie and Erica
Wood burning stoves, Rocket Mass Heaters, DIY,
Stove plans, Boat plans, General permiculture information, Arts and crafts, Fire science, Find it at www.ernieanderica.info
I need a new interior decorator. This tiny ad just painted every room in my house purple.
Greenhouse of the Future ebook - now free for a while