Insulation Never Stops Working Insulation, whether it’s fiberglass, wool, cellulose, or spray foam, are energy efficient technologies that, once manufactured, require no energy to save energy. Instead of reducing the amount of energy the use, like most “energy efficient” products, they actually save energy from being wasted. Not only does it save energy, it lasts for the life of the building and unless it is damaged, it will never have to be replaced. Now that’s efficient! So