The hidden cost of comfort: Regulatory blindness to humidity and a new energy poverty index for tropical housing

Prevailing thermal comfort and energy efficiency standards such as ASHRAE 55 and NEC HS-EE are fundamentally misaligned with the climatic realities of tropical regions, where relative humidity—rather than temperature—constitutes the dominant factor influencing occupant comfort. Both frameworks rely primarily on-air temperature and running mean calculations, neglecting the substantial influence of relative humidity. This simplification is particularly problematic in tropical climates, where high humidity levels frequently amplify the perception of heat, impair natural cooling mechanisms, and significantly increase the need for mechanical systems. This study evaluates the performance of low-income housing in coastal Ecuador using dynamic simulations under current and future climate scenarios, comparing energy demand outcomes for envelope designs compliant with NEC and ASHRAE standards. The results show that these standards, while effective in temperate climates, lead to internal overheating and substantially increased cooling loads when applied to tropical settings. Moreover, the inclusion of relative humidity in comfort analysis reveals that actual thermal conditions often surpass acceptable thresholds—even when operative temperatures fall within the normative comfort bands. To better reflect the lived thermal experience, a modified energy poverty indicator is proposed, integrating relative humidity as a key variable. Findings show that achieving real comfort conditions under high humidity may require up to ten times more energy than estimated by temperature-only models, pushing household costs beyond affordability limits. These results highlight a critical mismatch between prevailing standards and tropical climatic conditions, underscoring the need for more context-sensitive frameworks that explicitly address humidity-driven discomfort and its socioeconomic consequences.