Thank you for pointing that out, I should have set out my qualifiers, it is definitely not for everyone nor every use case. I favor the extremely stable properties and far lower environmental impact over XPS. For my specific use case, I want an application where the lifetime of the building is measured in >100 years, without having to go in and replace the insulation during that period, and without significant deterioration from the ocassional penetration of water or dampness. I wanted the natural flame retardant properties without doping in chemicals that have to be extracted out later with solvents (yielding its own set of recovery, recycling and disposal challenges) during recycling like we currently have to employ with recycling XPS (if the recycling facility extracts it out at all). I really like the concept of building this insulation once, and being able to re-use it indefinitely until it is physically compromised, capturing the embedded energy to make the insulation in a one-and-done cycle.

I'm not a huge fan of plastics or styrofoams outside of very well-contained use cases since its breakdown in the outside into extremely small pellets is already easily detectable in our seawater-based salt supplies, and unabated, I'm not sanguine about our keeping it from pervasively entering our food supply. The actual plastic itself I'm not too happy about mainly because it represents energy waste to me, and at least those types that have phytoestrogenic effects are still debatable. The doped compounds attached to those plastics however, I'm not terribly enthusiastic about that stuff leaching out into our environment and letting the sun and weather eventually breaking them down before they materially damage our bodies.

I'm not sure if with foamglass they mean an aerogel made of glass. That stuff has wild thermal properties.

https://www.youtube.com/watch?v=kz95RnIG0NY

If Chinese factories figure out how to mass produce aerogel, with similar durability and environmental footprints to Corning Foamglas (or similar foamed glass blocks), then I'd be all over that. So far though, I can't get very good field reports of people using the much cheaper pellet-form factor aerogel products commonly coming out of China.

I don't know the true manufacturing costs of sheet and block form aerogel, but they're priced so high that even multi-generational payback periods didn't pencil out even close, even granting them a 30% premium. Current manufacturers simply aren't aiming those form factors at building insulation as far as I can tell, though I'd love to be shown wrong.

For the time being, when I need near-aerogel-like qualities insulation but without the volume penalty foamed glass incurs, but can't justify the cost of aerogel due to the required quantity, I look to vacuum insulated panels to cover the big expanses of area and volume, and aerogel to fill in the gaps.