The extrusion process of uPVC window and door profiles is relatively energy efficient, compared with other materials. Another benefit: wherever uPVC has been specified as an alternative to wood, the rate of cutting of forests has slowed down. uPVC profiles are environmental friendly as they can be fully recycled and reused for the production of uPVC profiles. For several years now, all Koemmerling window and door profiles have been solely produced with calcium-zinc instead of lead. Calcium-zinc is a new type of stabilizer that makes uPVC profiles even more resistant to the most aggressive weather conditions.