I have an old house, with a fieldstone foundation and dirt floor in the crawl space. Prior to replacing old, deteriorating fiberglass insulation, I and my dog experienced multiple sinus problems, especially in the morning upon awakening. After installing Havelock Wool batts in-between the floor joists, plus installing a vapor barrier to cover the dirt floor, our sinus problems have dramatically lessened! Literally, we can breathe easier and cleaner! Humidity in the living area has lessened. House feels warmer. Recently I gave the remaining batts to a friend, who used to work in a factory that made fiberglass insulation. He was amazed at how clean the wool felt! and is even considering making the financial investment to help make his home more energy efficient in a cleaner, healthier way.
**Please note: I give a "2" on ease of installment because it was installed overhead in a crawl space, with irregular distances between floor joists, necessitating cutting the batts to make them fit. Havelock Customer Service and their videos were very helpful. The challenges of loving an old home!