The construction industry significantly contributes to global greenhouse gas emissions and consumption of raw materials, and is thus under intense pressure to become more sustainable. Despite the ever-increasing availability of sustainable solutions, they do not seem to be widely adopted. As key decision makers in the early planning stage of a construction project, end consumers strongly impact sustainable development. However, their knowledge of sustainability-related criteria and their influence on purchasing decisions within the German construction industry is not yet sufficiently well established. Therefore, this study aims to determine the effects of sustainability-related aspects on the purchasing behavior of private individuals, as end consumers in the German construction industry. A quantitative online survey involving 306 participants was utilized to determine their understanding of the term “sustainability” and how they identify and measure the sustainability of a building product. Our results indicate that consumers have a fundamental interest in sustainable building products; however, they lack a holistic view of the concept of sustainability. With the focus on environmental aspects, social and economic aspects tend to be neglected. Since private individuals rarely make purchasing decisions in the building product sector, it is the task of the entire construction industry to establish a system in which consumers can quickly and easily obtain understandable information about sustainable products. Consumers need support from experts to understand and drive sustainable development in the construction industry.