1 At CES we offer very different sustainability solutions depending on your expectations and goals. CES delivers, for example, broad and low carbon energy, nearly zero-emission buildings (NZEB) or zero-energy solutions for construction projects or refurbishments. That is why we are driven to meet your vision on sustainable real estate development. The value of each project is reflected in specific energy or quality labels. These labels are not always required by law, but often have a commercial added value for the sale or rental of a building. In general, sustainability studies are carried out before the final design phase as the choices have an impact on the building architecture and technical installations