While teaching a class last night on wood gasification (per emergency energy stoves) I talked about insulation. It was an on-hands class and I was applying vermiculite noting that it has a 1.5R value per inch and mentioned that the vintage 1915 log home on our ranch (while growing up) had vermiculite filled between the studs in the attic in the ceiling rather than the fiberglass. A young gal student asked- “why is it (fiberglass insulation) pink”?
To tell the truth, only some is pink and it is dyed as such by a vendor as a way to match with their marketing. Owens Corning has the Pink Panther as their mascot and dyes the resin so you will think this company which up with fiberglass almost 90 years ago. Fiberglass itself doesn’t have a hue, and some other minor companies die theirs green (and I’ve even seen brownish fiberglass).
What makes it warm? Glass itself is a poor conductor of heat and it is non-combustible. The spun glass has little pockets of space to hold the air and its warmth. Vermiculite has some similar qualities as the extruded mica (tannish silica) has air pockets in its light layers. Perlite is another mined material per se which when baked at the manufacturing plant expands it and has heat retention value; it is a white substance. Blow in cellulose is the brown color of cardboard and it has pocketing for warm retention as well.
So there are several substances that can insulate and color is variable, not really making a difference in the insulation value itself. A good question though, as many from engaged attendees are!