can't answer for all of them, we are now on our second house insulated by a firm called stoneham insulation, they use a mineral product called rock wool. It is non toxic, doesn't degrade in the walls doesn't settle and installation was a painless, clean process. it cost us 700 quid to do a large 4 bedroom in 1988. the difference to comfort and heating bill was quite noticeable. We got a guarantee with it that is for the life of the house and includes all future owners of the house.