Earthcore’s Isokern line has become the most trusted modular system in the world. Isokern Fireplace & Chimney components are lightweight, while retaining UL 127 and UL 103HT (respectively) listings. Consequently, our Isokern Fireplace & Chimney Systems are less expensive to install than traditional masonry fireplaces. And, unlike typical metal box fireplaces or concrete systems, they are built to last forever.