Aluminum Foil Bubble EPE Foam insulation is manufactured with a closed cell foam structure with one layer of bubble between two sides highly reflective aluminum foil surfaces, it is the fiber-free,non allergenic alternative to conventional bulk insulation. In Summer, it will stop 97% of the summer heat gain due to radiation across your roof space. In Winter, it is effective in reducing winter heat loss. Instead of losing all the heat it will be reflected back into your home, keeping your home warmer by between 6-8 degrees.