The United Nations is set to release a Roadmap for Passive Cooling in the ASEAN Region next month.
The roadmap includes cost-effective alternatives to energy-intensive mechanical cooling such as passive cooling strategies, encompassing natural ventilation, shading, reflective surfaces, thermal mass, and climate-responsive building design.
These approaches can deliver indoor temperature reductions of 2–4°C under typical conditions and up to 8°C in optimised designs, with energy savings of 20–50 per cent depending on the measures applied.
At regional scale, passive cooling and nature-based solutions could curb cooling capacity demand growth by 24 per cent by 2050, potentially saving up to $US 3 trillion in avoided cooling equipment costs and reducing emissions by 1.3 billion tonnes of CO₂e.
Critically, passive cooling is accessible and affordable, providing inclusive thermal comfort for the 1.2 billion people globally who currently lack access to adequate cooling.
The ASEAN Centre for Energy (ACE) and the United Nations Environment Programme (UNEP) Cool Coalition, in collaboration with the United Nations Economic and Social Commission for Asia and the Pacific (UN ESCAP), the Global Alliance for Buildings and Construction (GlobalABC), and UN Women’s EmPower II Programme, developed the Roadmap.
The ASEAN urban population is projected to surge from 348 million in 2022 to 521 million by 2050, and ASEAN cities could experience up to 120 days per year with temperatures above 35°C by mid-century.
The urban heat island effect compounds these risks in dense urban centres in ASEAN Member States (AMS), where heat-absorbing materials, diminishing green spaces, and poor ventilation trap heat and create dangerous indoor environments.
At the same time, soaring demand for mechanical air conditioning is driving electricity consumption, greenhouse gas emissions, and peak grid loads higher, creating a self-reinforcing cycle that further accelerates the warming crisis.
The roadmap translates the region’s heat resilience challenges into actionable policy directions, financing mechanisms, and capacity-building pathways adaptable at the national level.
It promotes a “Passive First” design philosophy, prioritising building orientation, envelope performance, shading, and ventilation to minimise cooling demand before specifying mechanical systems.