Cambodia Champions Passive Cooling to Tackle Heat and Cut Energy Demand

As temperatures rise and urbanisation accelerates across Southeast Asia, Cambodia is emerging as a regional pioneer in passive cooling, a set of building design strategies that reduce heat indoors without relying on energy-intensive air conditioning. With cooling demand projected to double by 2040, the country faces mounting pressure on energy systems alongside growing greenhouse gas emissions and urban heat risks.

Buildings already account for around one third of Cambodia’s final energy consumption, with space cooling representing the largest share of electricity use. In response, passive cooling was identified as a priority in Cambodia’s National Cooling Action Plan, positioning natural, low-energy design solutions as a foundation for managing future cooling demand.

To turn policy ambition into practical change, the Ministry of Environment of Cambodia, with technical and financial support from the United Nations Economic and Social Commission for Asia and the Pacific (UN ESCAP) and UNEP within the Cool Coalition framework, launched the Passive Cooling Strategies for Sustainable Development in Cambodia project. Its central outcome, the newly released Guidelines for Passive Cooling Strategies in Cambodia, was officially unveiled at a regional event in Phnom Penh attended by government leaders, technical experts, building sector professionals, universities, and international partners. 

The Guidelines offer a practical, climate-specific roadmap for architects, engineers, policymakers, and the wider public. They show how strategies such as cool roofs, shading, insulation, building orientation, natural ventilation, and landscape design can be applied across building types to improve thermal comfort while reducing reliance on mechanical cooling.

Importantly, the guidance is grounded in technical analysis and real-world performance data from a demonstration building in Phnom Penh developed under the project. Monitoring results highlighted improvements in comfort and energy efficiency, providing concrete evidence that passive cooling can deliver meaningful benefits even in Cambodia’s hot-humid climate.

Beyond technical design, the Guidelines also include performance requirements intended to support future integration into building energy regulations, strengthening long-term policy impact. 

The launch of the Guidelines marked the culmination of a broader programme aimed at transforming Cambodia’s building sector. Alongside developing policy-ready design guidance, the initiative has supported regulatory integration, delivered capacity-building and awareness activities, and contributed technical input to Cambodia’s updated climate commitments under NDC 3.0.

The following day, momentum continued with a hands-on workshop organised by the Cambodia Passive Cooling Community of Practice chaired by the Institute of Tehcnology of Cambodia (ITC), supported by national institutions, UN ESCAP, and the UNEP Cool Coalition. The project team provided a comprehensive training on application of the new Guidelines to real design scenarios, explored cost and life-cycle considerations, and linked passive cooling strategies to national energy efficiency and climate resilience goals. The workshop also brought together students, recent graduates and young professionals alongside experienced practitioners, creating space for emerging voices to present their research, share hands-on experience with passive cooling strategies, and contribute to discussions on next steps for the community.

During the same week, the Cool Coalition also released an exclusive interview with Mark Low of Urbanland, highlighting private sector uptake of passive cooling in residential developments. Together, these actions demonstrate how Cambodia is moving from policy recognition to practical implementation.

By embedding passive cooling into design practice, regulation, and climate strategy, Cambodia is positioning itself as a regional model for addressing rising heat while advancing sustainable development and emissions reduction.