Science Behind Setting the Right AC Temperature

13 Jun 2025 GS 3 Environment
    Live Views: Loading...


(UPSC Prelims – Energy, Environment, Standards; Mains GS-III – Energy Conservation, Public Health, Environment)

Context:

  • The Union Ministry of Power plans to restrict AC temperature settings to between 20°C and 28°C.

  • Applies to households, hotels, and cars.

  • Objective: Energy conservation + public health.

Key Energy Benefits:

  • Every 1°C increase in AC temperature saves 6% electricity.

  • Default setting proposal: 24°C.

  • Potential savings: 20 billion units/year.

  • By 2030, connected AC load in India expected to reach 200 GW.

  • Backed by the Bureau of Energy Efficiency (BEE) study.

Key Health Insights:

  • 18–21°C range is considered “uncomfortable and unhealthy”.

  • Below 18°C:

    • Increased blood pressure, risk of hypertension

    • Risk of respiratory issues, especially in children and elderly

    • Reduced lung function, higher cholesterol, and weaker grip strength

    • Mental health impact: Higher depression/anxiety risk in persistently cold homes

  • Comfort range: 20–24°C (ASHRAE-55 & ISO 7730 standards)

  • WHO’s 2018 Housing and Health Guidelines recommends 18°C minimum in living spaces for temperate/cooler climates.

AC Functioning – Energy Implications:

  • ACs operate via vapour-compression cycle using refrigerants:

    • Evaporator absorbs heat → Compressor (high power usage) → Condenser releases heat → Expansion valve.

  • Greater the temperature difference, higher the energy required to pump heat.

Population-Specific Observations:

  • Children breathe better when ACs are above 18°C.

  • Infants & elderly prefer higher temperatures due to weaker thermoregulation.

  • For healthy adults, sleep improves in the 16–19°C range, but only in short durations.

📘 About Bureau of Energy Efficiency (BEE):

  • Established: March 2002 under the Energy Conservation Act, 2001

  • Nodal agency under the Ministry of Power

  • Key functions:

    • Develop energy efficiency policies & programs

    • Run Standards & Labeling Program for appliances (e.g., star rating for ACs, fridges)

    • Promote energy-saving tech and public awareness

    • Help implement the Energy Conservation Building Code (ECBC)

    • Conduct energy audits, certify energy managers/auditors

UPSC Relevance:

Prelims:

  • Default AC temp: 24°C

  • BEE role in energy efficiency

  • ASHRAE-55 and ISO 7730 – Comfort standards

  • WHO safe temp: ≥18°C

Mains (GS-III):

  • Link between energy policy and public health

  • AC usage and climate-resilient infrastructure

  • Role of behavioral change and policy nudges in sustainability



← Back to list