Notes for Students
Topic: Science behind regulating AC temperature range
Context of the Article: The Union Ministry of Power is considering mandating a fixed temperature range (20°C–28°C) for air conditioners in homes, hotels, and vehicles to promote energy efficiency and public health.
UPSC Paper Topic Belongs To: GS Paper 3 – Environment and Energy Security GS Paper 2 – Health and Government Policies
Dimensions of the Article:
- Government initiative for energy conservation
- Health risks of low indoor temperatures
- Working of air conditioners and energy consumption
- International standards on thermal comfort (ASHRAE, WHO)
- Climate change and equitable access to cooling
Current Context
The Union Ministry of Power is considering mandating a fixed temperature range (20°C to 28°C) for air conditioners in India across households, vehicles, and hotels. This decision is driven by two major factors: energy conservation and public health benefits. Previous efforts in 2018 and 2021 had already proposed setting a default AC temperature at 24°C, and now the push is toward formal regulation. Scientific research and health studies increasingly support this initiative.
Feature
- Energy Efficiency and Savings Fact from News:
- Each 1°C increase in AC temperature can reduce electricity consumption by 6%.
- Setting ACs to 24°C could save 20 billion units of electricity annually.
- The total connected load due to ACs is projected to reach 200 GW by 2030.
Explainer:
Air conditioners use the vapour-compression cycle, which consumes more power as the difference between room temperature and outdoor temperature increases. For example, maintaining 18°C in a 35°C environment requires more work than maintaining 24°C. Raising the temperature setting reduces compressor workload, leading to lower power consumption, less strain on the grid, and lower electricity bills. Given India’s growing demand for ACs, optimizing temperature settings can greatly reduce national energy demand.
- AC Working Principle and Efficiency Zone Fact from News:
- Refrigerants operate most efficiently within certain temperature ranges.
- Most power is consumed during the compression phase of the cycle.
Explainer:
The AC system absorbs heat from the room and dumps it outside. The compressor, which converts low-pressure vapour into high-pressure superheated vapour, is the most energy-intensive part. Operating ACs in the 20–28°C range allows the refrigerant cycle to function within its optimal thermodynamic efficiency, minimizing waste and energy loss.
- Health Risks of Low Indoor Temperatures Fact from News:
- Temperatures under 18°C have been linked to higher blood pressure, asthma, and respiratory infections.
- Long-term exposure can lead to hypertension, lower vitamin D, depression, and reduced lung function in both children and older adults.
- WHO recommends a minimum indoor temperature of 18°C in temperate/cooler regions. Explainer:
Too-cold environments cause vasoconstriction (tightening of blood vessels) and activation of the sympathetic nervous system, elevating blood pressure and increasing the risk of cardiovascular disease. Children and elderly people, with less efficient thermoregulation, are more vulnerable. Also, cold indoor air can dry out airways, increasing chances of infections and asthma attacks. Mental health can also deteriorate in persistently cold homes, regardless of income levels.
Fact from News:
- Comfort is defined where the human body maintains core temp (~37°C) and skin temp, without sweating or shivering.
- ASHRAE-55 and ISO 7730 standards allow a range depending on clothing, culture, and technology.
- Ideal temperature range for resting: 20–24°C for most, 16–19°C for healthy adults during sleep.
Explainer:
Thermal comfort is not one-size-fits-all. People in tropical countries may feel comfortable at higher indoor temperatures. Standards like ASHRAE-55 adapt for these differences. But consistently running ACs below 18°C deviates from recommended norms and is unnecessary for most people’s comfort. The proposed 20–28°C regulation aligns with global best practices for both comfort and energy efficiency.
5. Cooling Access and Climate Challenge Fact from News:
- As of 2022, only 43% of the Asia-Pacific had sufficient access to cooling.
- AC units worldwide have grown from 500 million to 2 billion since 2000.
Explainer:
Energy-efficient AC usage ensures more equitable access to cooling without overwhelming power grids. India, with rising heatwaves and expanding AC markets, must adopt smart usage norms to balance climate adaptation with sustainability. Setting regulated temperature limits prevents overcooling, making cooling accessible, healthy, and climate-resilient.
Conclusion:
The proposal to regulate air conditioner temperatures between 20°C and 28°C is backed by solid evidence in energy economics, environmental sustainability, and public health. With air conditioner usage rising steeply, this measure could save billions of units of electricity, reduce greenhouse gas emissions, and prevent lifestyle-related health issues.
Rather than being a restriction, it represents a scientifically informed optimisation of AC usage in India’s specific socio-climatic context. To make it effective, it must be paired with consumer awareness, manufacturer compliance, and policy clarity, ensuring both climate goals and public welfare are met.
