Several studies on sustainable technologies for the built environment (e.g., green roofs, green walls, etc.) have been carried out. Many of these focus on the technical performance of such technologies. Nonetheless, it also becomes necessary to examine how the public perceives such technologies. This understanding is clearly important to support their widespread use. More specifically, such perception can be incorporated into product design to increase people's acceptance. The contribution of this paper is twofold. First, it presents results of a survey examining the perception of people from a small city in the Southern region of Brazil (Feliz, RS) regarding three sustainable technologies: green roofs, green walls, and composting (or dry) toilets. Second, it proposes a set of preliminary design guidelines to improve acceptance of more sustainable technologies based on people's perception: (1) make the technology look good; (2) make visible the benefits provided by the technology; and (3) design the technology to avoid misunderstandings and concerns. (C) 2016 American Society of Civil Engineers.