Spray foam is susceptible to UV exposure, which may compromise its performance. Fiber glass insulation and mineral wool insulation are UV stable, meaning they do not experience shrinkage or thermal performance loss with exposure to ultraviolet rays. Fiber glass and mineral wool batts do not settle-and loose-fill fiber glass and mineral wool only settle a negligible amount-so their thermal performance is maintained for the life of the building.
According to the NAHB (National Association of Home Builders) Research Center and several other independent tests, when fiber glass insulation and mineral wool insulation are paired with standard air sealing practices (including taped house wrap or caulk), air infiltration is effectively reduced to near zero. So aim to get the most R-value for your budget in your chosen insulation material. You may see a product that claims to be a “superior insulator” because it achieves a higher R-value per inch of insulation, but all products with the same R-value can insulate equally well. Given the fact that all insulators are equal when properly installed and air sealed, the goal is to maximize the R-value you achieve for the dollar you spend. 1 Still, there are several factors to consider when comparing insulation types. When choosing an insulation product, it’s important to understand that there’s no such thing as a “superior insulator.” According to the Building Sciences Corporation, all types of insulation perform equally well when properly installed and air sealed.