Developing lower GWP foam plastics results in a really large reduction of greenhouse gas dumped directly into the atmosphere at a mission critical moment for GWP reduction. Insulation has so many uses beyond thermal resistance in most enclosures, that rejecting any one material out of hand will get you in trouble with the other things you’re trying to accomplish with that material. At the same time, foam plastics still give the best R-value/inch of any insulation material type (with the possible exception of Aerogel – which is manufactured with plastic in tape and spray form), and they do some things (combining vapor, air and water control) that no other insulation material does. Whether it’s wood/fiber-based, mineral-based or petroleum-based, everything has a range of drawbacks and toxicities, recycling and life cycle issues, which have to be considered and worked through, especially at scale. There is no magic bullet. There is no simple answer. There’s just a lot of work that all of us have to do.
Regards,