Introduction Disruptions to global supply routes have exposed Asia’s dependency on imported fuel and how quickly that dependence translates into pressure on public budgets and essential services. Governments are ordering cuts across public institutions, including hospitals. But unlike offices, schools, and other public agencies, hospitals cannot reduce hours, send staff home, or dim the lights. They run 24 hours a day, 7 days a week, caring for patients who cannot wait. In practice, hospitals are designed to stay operational when it matters most, with reliable energy supply, proper ventilation and air filtration, and safe water and waste management that can keep functioning when external systems fail. In hospitals, energy, health, and indoor air quality are all interlinked with essential air conditioning and ventilation, typically accounting for at least 50%–60% of energy consumption in large facilities. A hospital that generates its own energy and uses it efficiently is not only greener, but it is safer, more affordable to operate, and more resilient when people need it most. Why does air quality matter so much more in hospitals than in other buildings? Hospitals are not ordinary buildings. They are places where infectious diseases are diagnosed and treated, and where immunocompromised patients share enclosed spaces with staff and visitors. The COVID-19 pandemic made it clear that inadequate ventilation systems can become highways for the airborne spread of pathogens. Viruses can survive in the air for several hours in aerosols, with droplet transmission facilitated by poorly managed air-conditioned ventilation. The next outbreak is a matter of when, not if—and hospitals that cannot control their air environments will remain unprepared for it. Hospital air must be not just comfortable, but clinically safe and pandemic-resilient. What is the ideal air circulation in a hospital? International standards set by the World Health Organization (WHO) and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 170 define specific requirements for hospital ventilation, including air change rates, temperature ranges, humidity levels, and filtration standards. Critically, different areas of a hospital require entirely different air environments (Figure 1). Operating rooms must maintain positive pressure for clean, filtered air that is continuously pushed outward, so that no outside air carrying potential contaminants can enter a sterile surgical field. Isolation rooms for infectious patients require negative pressure, so contaminated air is contained and cannot escape into corridors and wards. Immunocompromised patients—those on chemotherapy or awaiting transplants—require the reverse to keep pathogens out. Air filters are rated on a Minimum Efficiency Report Value (MERV) scale from 1 to 16. A higher rating indicates a greater ability to capture particles. For reference, a household air conditioner typically rates MERV 1 to 4, while hospitals require at minimum MERV 13 in high-risk areas. Split-type air conditioning units simply cannot meet this standard. Managing these zones correctly is the difference between a hospital that controls infection and one that spreads it. Figure 1: Hospital Zoning for Air Quality Management Click on image to enlarge.Note: Different hospital areas require specific pressure controls and filtration standards to ensure optimal infection control and patient safety. Pink zones (surgery and emergency departments) maintain positive pressure; red zones (isolation and diagnostic areas) use negative pressure; green zones (general rooms) have positive pressure; gray zones (utility areas) maintain negative pressure; and blue zones (public areas) focus on proper ventilation.Source: Asian Development Bank. Conceptual Design for Ventilation and Cooling Systems in Health Care Facilities. Technical Assistance 6563: Regional Support to Build Disease Resilient and Energy Efficient Centralized Air-conditioning Systems funded by the Clean Energy Financing Partnership Facility and High-Level Technology Fund. How do most hospitals in Asia handle their cooling needs? Despite clear standards, many hospitals across developing Asia continue to rely on the same split-type air conditioning units found in homes and small offices. These units lack sophisticated air filtration, cannot manage positive and negative pressure zones, and have no capability for ensuring fresh air circulation in line with WHO and ASHRAE requirements. Apart from being unsafe, these are also inefficient. Under Technical Assistance 6563, Asian Development Bank (ADB)-supported energy audits at four Philippine government hospitals found systematic inefficiencies, including systems running simultaneously to achieve minimum cooling and basic maintenance failures compounding energy waste. These findings are not unique to the Philippines; similar patterns have been observed across the region. Figure 2: International Standards and Technical Solutions for Hospital Heating, Ventilation and Air-Conditioning Systems Click on image to enlarge.Note: Modern Hospital Heating, Ventilation and Air-Conditioning systems must comply with WHO and ASHRAE standards for indoor air quality, thermal conditions, and ventilation (top panel). Meeting these standards requires deploying appropriate technologies including air handling units, chillers, filtration systems, and specialized equipment for different hospital areas. Air filter efficiency ranges from basic MERV 1–4 filters to highest efficiency MERV 13–16 filters depending on the application (bottom right panel).Source: Asian Development Bank. Conceptual Design for Ventilation and Cooling Systems in Health Care Facilities. Technical Assistance 6563: Regional Support to Build Disease Resilient and Energy Efficient Centralized Air-conditioning Systems funded by the Clean Energy Financing Partnership Facility and High-Level Technology Fund. What are effective cooling options for hospitals? Modern centralized air-conditioning systems with variable refrigerant flow, smart controls, proper zoning, and filtration units can cut energy consumption by 30%–50% compared to conventional split-type air conditioning systems, while simultaneously meeting WHO and ASHRAE infection control and air quality standards. For existing buildings, further savings can be achieved by retrofitting the building envelope (adding insulation, cool roofs, and improved glazing) to reduce the cooling load before it even reaches the air conditioning system. The evidence is there. At one Philippine government hospital, a detailed audit shows that switching to an appropriate centralized system could save over $130,000 annually. In Sri Lanka, ADB's pilot of smart air-conditioning in public buildings delivered 30%–40% reductions in energy consumption, with a return on investment within 5 years. These investments pay back in lower energy bills, better care, and lives protected. How do countries finance better cooling systems? Financing climate-resilient health infrastructure requires intentional bridging across sectors, connecting the health standards that must be met with the energy technologies that can meet them. ADB bridges governments, ministries, and technical experts who rarely sit at the same table. In the Philippines, ADB's Build Universal Health Care Program embedded energy efficiency requirements into health policy agreements, creating the institutional legitimacy for the Department of Health to catalyze technical support from the energy sector. This led to a landmark memorandum of agreement between the Department of Health and Department of Energy, and hospital managers being trained and accredited as Green Professionals. The recently completed Philippine Health System Integrated National Accounting of Greenhouse Gas Emissions (PH-SINAG)—the world's first national health system GHG baseline fully compliant with WHO Alliance for Transformative Action on Climate and Health guidance—revealed that electricity accounts for 16% of the health system's carbon footprint. In Cambodia, ADB pivoted $93 million toward green hospital construction under the Cambodia Rapid Immunization Support and Resilient Health Infrastructure Project, with new hospitals built climate-resilient from the ground up. Conclusion Hospitals cannot switch off. As energy prices reshape public budgets across Asia, safer hospitals and more energy-efficient ones turn out to be the best investment. The technology exists, the evidence is there, and the financing is available. Resources Asian Development Bank (ADB). 2023. Disease-Resilient and Energy-Efficient Smart Air-Conditioning Systems in Asia and the Pacific. ADB. 2023. Piloting Disease-Resilient and Energy-Efficient Smart Air-Conditioning Systems in Public Buildings: Sri Lanka. World Health Organization. 2024. Safe, Climate-Resilient and Environmentally Sustainable Health Care Facilities: An Overview. WHO. Ask the Experts Eduardo P. Banzon Director, Health Practice Team, Human and Social Development Office, Sectors Department 3, Asian Development Bank Dr. Eduardo Banzon champions Universal Health Coverage and has long provided technical support to countries in Asia and the Pacific in their pursuit of this goal. Before joining ADB in 2014, he was President and CEO of the Philippine Health Insurance Corporation, World Health Organization (WHO) regional adviser for health financing for the Eastern Mediterranean region, WHO health economist in Bangladesh, and World Bank senior health specialist for the East Asia and Pacific region. David Morgado Senior Energy Specialist, Sectors Department 1, Asian Development Bank David Morgado supports regional and private sector departments at ADB, focusing on energy efficiency and emerging technologies. He previously worked at AIIB, implementing their Energy Strategy, and at the IEA, enhancing energy efficiency in Brazil, India, and Mexico. At the IIEC in Thailand, he provided technical assistance on energy efficiency and renewable energy across Asia-Pacific and Africa. David holds an MSc in Environmental Sustainability from the University of Edinburgh. Romelei Camiling-Alfonso Health Systems Specialist Romelei Camiling-Alfonso has expertise in facilitating cross-sectoral collaboration. As a health facility expert consultant for the Asian Development Bank's Build Universal Health Care Program, she helped connect health and energy sector stakeholders, creating space for vital dialogues that strengthened energy efficiency and climate resilience in Philippine health facilities. In her current role as health innovation consultant, she is bringing this collaborative approach to digital health initiatives across Asia and the Pacific. Leave your question or comment in the section below: View the discussion thread.