Systematic review of nanocoatings for building envelopes: thermal, radiative, and durability trends across materials and climatic contexts

• Systematic review of 97 studies on nanocoatings across five building envelope materials. • Semi-quantitative framework enables cross-material and climate-responsive comparison. • Glass and metal substrates show the most consistent energy-performance improvements. • Climatic context strongly influences effectiveness and durability of nanocoatings. • Limited long-term evidence (<12 months) constrains lifecycle energy assessment. • Clear distinction established between material-, envelope-, and building-scale evidence. • Identifies key gaps in durability validation, climate-specific testing, and standardization. Advancements in nanocoating technologies are transforming the energy performance of building envelopes. Unlike conventional insulation or glazing systems, nanocoatings offer ultra-thin surface treatments that regulate thermal flow, solar radiation, and heat transfer without altering architectural form or requiring structural modification. Despite their growing potential, current research remains fragmented and often confined to single-material analyses or laboratory-scale evaluations. This study presents a systematic and comparative review of peer-reviewed literature published between 2000 and 2026, focusing on nanocoatings applied to five major envelope materials: glass, concrete, metal, wood, and composites. Following PRISMA-based selection criteria, 97 studies were extracted from four leading databases and interpreted through a qualitative multi-dimensional analytical framework enabling structured cross-comparison of coating types by substrate, functional role, and key performance indicators: emissivity, reflectivity, and thermal conductivity, alongside climatic suitability and durability. Findings reveal that nanocoatings can enhance solar control and thermal regulation under appropriate material, climatic, and application conditions, particularly when tailored to material properties and specific climatic contexts. Glass and metal substrates show the most consistent improvements in solar reflectivity, while porous materials such as concrete and wood display variable thermal behavior influenced by surface morphology. Persistent gaps remain in long-term performance validation, cross-material optimization, and climate-specific assessment. By integrating materials science, environmental context, and architectural energy strategies, this study proposes a comprehensive evaluative framework to inform future research and guide designers, engineers, and policymakers in leveraging nanocoatings for energy-efficient and climate-adaptive building envelopes.