Environmental Sustainability and Energy Efficiency in Twentieth-Century Architecture: Key Paradigms, Drawbacks and Design Lessons

The twentieth (20th) century represents a radical transformation in architectural history. Unlike previous centuries, characterized by gradual stylistic continuity, it witnessed a succession of theoretical ruptures, technological innovations, material discoveries, and experimental design paradigms. Each movement emerged by questioning the assumptions of its predecessors, generating an experimentation laboratory that transformed the relationship between buildings, resources, climate, and society. Despite this exceptional intellectual and technological legacy, 20th-century architecture is still predominantly interpreted through its technological shortcomings, while the historical evolution of its contributions to environmental sustainability and energy efficiency is still lacking. This study reconstructs the historical genealogy of environmental sustainability and energy efficiency across the principal architectural movements of the 20th century. Through a comparative analysis of design theories and architectural principles, it identifies environmental and energy paradigms, drawbacks, and design lessons. Environmental sustainability evolved around material durability, adaptability, resource optimization, contextual integration, and life cycle thinking, whereas energy efficiency developed through passive climatic strategies, building morphology, envelope performance, daylight, natural ventilation, and environmental control. The study demonstrates that many of the principles underpinning contemporary sustainable and energy-efficient architecture originated during the 20th century. Approaches such as Parametricism, Computational Design, Biomimetic Architecture, Climate-Responsive Design, Circular Architecture, and Regenerative Design extend these concepts through new scientific understanding, digital technologies, and environmental performance objectives.