The aim of this textbook is to improve conventional building design in Southeast Europe. This is done with proposing conceptual guidelines for designing energy-efficient buildings for different geographic regions of Serbia. The focus is on climate-appropriate design of building envelopes. To adress sustainability, economical, environmental and social aspects are evaluated. The body is divided into three main chapters: traditional houses, the existing housing stock, and design patterns for future buildings. The conclusions and the methodology can be applied in the rest of Southeast Europe, since Serbia has a unique position in the middle of the region, covering different geographical areas that spread far out of Serbia’s borders.