The Passive House standard is recognized as one of the most rigorous frameworks for building energy efficiency and thermal comfort, typically defining an indoor temperature range of 20-25°C. While this band aligns well with comfort expectations in cooler and temperate regions, it often fails to reflect local comfort preferences in Very Hot climates classified by the standard. Occupants in these regions are exposed to prolonged cold discomfort and related health risks when spaces are maintained at such low setpoints. At the same time, applying this narrow band inflates calculated cooling demand which makes compliance more difficult and limits the feasibility of Passive House adoption.
Field studies across Southeast Asian countries with the Very Hot climate classification provide clear evidence of this mismatch. In Singapore and Thailand, a probit analysis showed that temperatures of 23.6-26.4°C (Singapore) and 22.9-25.6°C (Thailand) in air-conditioned offices were acceptable for most occupants (Sikram et al., 2020) In the Philippines, where tolerance to cold is particularly low, prolonged exposure to 20-23°C has been linked to thermal discomfort, increased risk of illness, and reduced satisfaction in air-conditioned offices (Orduña, 2025). Collectively, these findings highlight how applying a fixed 20-25°C standard in Very Hot climates undermines both occupant well-being and the practicality of Passive House certification.
Using the Philippines as a case study, this research challenged the assumption that thermal comfort in Very Hot climates can be universally defined by Passive House's fixed indoor range of 20-25°C. It proposed climate-sensitive comfort thresholds that reflect local adaptation, cultural expectations, and health needs. By aligning these thresholds with regional evidence, the study demonstrated that occupant well-being can be safeguarded while also making compliance with the Passive House standard more realistic in Very Hot climates.