Missing home cooling solutions: India’s next big energy challenge is close to home — the swelter inside millions of dwellings. Residential space cooling is on track to become the dominant driver of electricity demand as summers intensify and incomes rise. The cooling energy demand is expected to grow several-fold by 2037–38, with space cooling alone accounting for the lion’s share and cooling-related emissions nearing 7% of national totals unless policy and design course-correct now. At the same time, extreme heat is eroding productivity and health: the ILO estimates India could lose 5.8–6% of working hours by 2030 from heat stress, with millions of jobs at risk, while national and state heat-action plans continue to grapple with avoidable mortality.
India must prioritise design innovations — better insulation, passive cooling, and smart materials — so households need less mechanical cooling to begin with. Solutions must be state-specific, reflecting sharp differences in climate and income. Financing and market models should lower first costs, but good design is the cheapest decarbonisation strategy.
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India’s power system is already stretched by record summer peaks, much of it from residential air-conditioners running in unplanned, inefficient buildings. In cities such as Delhi, between 40 and 60 per cent of summer peak demand is attributed to space cooling, straining grids and forcing costly standby generation. Meeting this rising demand through conventional power expansion will lock in higher fossil-fuel dependence, undermine climate targets, and saddle distribution companies with unsustainable losses. Reducing the need for mechanical cooling through better design is, therefore, as much an energy-security imperative as a climate commitment.
Passive cooling and insulation
Global evidence is unambiguous: efficient, climate-friendly cooling can slash peak power needs and emissions while saving consumers money. In India, the Eco-Niwas Samhita (ENS) — the residential energy code — already prescribes building-envelope standards to limit heat gains and promote daylighting and ventilation; the code is purposely simple so architects can apply it at design stage. Affordable-housing case studies show what this means in practice: low-U walls, shading, smaller window-to-wall ratios, cross-ventilation, and reflective roof finishes have lowered peak indoor temperatures by >5°C and halved hours of thermal discomfort, reducing the need to buy and run ACs.
ENS remains voluntary across much of India. Making ENS compliance mandatory in municipal by-laws, with simple compliance tools and on-site checks, would mainstream passive design in new homes and retrofits alike. The case is not merely environmental; it is fiscal. Every degree of avoided indoor heat defers expensive generation and distribution capacity that would otherwise be built to meet a few torrid hours of peak demand each year. The ICAP and the UNEP-IEA synthesis have framed this explicitly as a peak-mitigation strategy.
Cool roofs and smart materials
Among “smart materials”, cool roofs are the fastest to deploy and the easiest to understand. Telangana’s state-wide Cool Roof Policy (2023–28) — mandating cool roofs in phases and scaling through urban local bodies—provides a template for others. Pilots in Ahmedabad and Hyderabad documented 2–5°C lower indoor temperatures in low-income homes and meaningful energy savings; recent research suggests that lifting cool-roof coverage from 5% to 20% of residential roofs in Ahmedabad by 2030 could fully offset additional AC demand due to warming.
The appeal is not just thermal: reflective and high-albedo materials cut cooling loads at source, benefit those without ACs, and are cost-effective at scale. A growing body of municipal heat-action plans now embed cool-roof targets and public procurement standards. The centre can accelerate adoption by listing cool-roof materials with performance labels on GeM and linking them with housing schemes and disaster-resilience grants.
Climate zones and income must shape design
India is not one climate; it is five—hot-dry, warm-humid, composite, temperate, and cold—as per the ECBC/ENS framework, and district-level tools now let planners identify the relevant zone. Design prescriptions should vary accordingly:
Hot-dry (Rajasthan, parts of Gujarat/Maharashtra): Insulated roofs and walls, shaded courtyards, night-purge ventilation, and thermal mass pay back quickly.
Warm-humid (coastal Andhra, Odisha, Kerala): Cross-ventilation, shaded verandahs, high-permeability windows, and moisture-managing materials trump heavy insulation; reflective roofs help but must be paired with ventilation.
Composite (Delhi, UP, MP): Adaptive envelopes with seasonal operability (shading + insulation) and ceiling fans (preferably BLDC) reduce AC hours drastically.
Temperate/Cold (hill states): Airtightness, double glazing, and roof/wall insulation matter as much for winter heating as for summer comfort.
Crucially, income dispersion across states—and within cities—must shape choices. Official data show order-of-magnitude gaps in per-capita income (e.g., Bihar vs. Goa/Karnataka), highlighting why low-capex measures (cool roofs, shading, fans, ventilation) are essential for equity, while higher-capex envelope retrofits can be targeted via concessional finance in richer markets.
Financing models for affordable home cooling
Even with good design, many households will still adopt ACs as temperatures rise. The objective then is to buy the most efficient appliance and run it less. India’s public programmes have demonstrated how markets can be shifted:
Bulk procurement/ESCO: EESL’s Super-Efficient ACs (SEAC) pushed the market toward higher ISEER models and delivered ~22% price reductions in early phases—proof that aggregated demand can bend prices.
Efficient-product access: Today, SEAC models with ISEER 5.8–6.2 are sold at competitive prices, showing that high efficiency need not be premium-priced if procurement and after-sales are bundled.
On-bill financing (OBF): Internationally proven, OBF can unlock efficient fans and RACs for low-income households by recovering instalments via utility bills; the World Bank and others have identified large DSM-linked savings if state regulators set clear targets.
Pair these with service models (cooling-as-a-service for apartments and rental markets) so that performance, not ownership, is what households pay for—and so providers are incentivised to design for lowest lifetime energy use. (India’s own pilots in cold chains and commercial buildings show the model’s promise.)
Heat is not only an electricity problem; it is a public-health and labour-economics problem. The ILO’s projected millions of job-equivalents lost and the NDMA’s continuing focus on zero heat-wave deaths place thermal comfort squarely within livelihoods and welfare. A design-first approach delivers benefits even to the AC-less majority, especially women, children and the elderly who spend more hours indoors. Recent on-ground evidence—from Reuters’ coverage of cool-roof trials in Ahmedabad to medical reviews—confirms the health dividends of lower indoor temperatures.
A five-point design-led decarbonisation plan
Mandate ENS in municipal building by-laws within 12 months; publish zone-wise, income-sensitive pattern books of passive designs for self-builders and PMAY projects.
Scale cool roofs: emulate Telangana’s policy statewide; ring-fence urban-climate funds for reflective roofs, green roofs where feasible, and performance-labelled materials on GeM.
Target appliances smartly: accelerate bulk procurement of BLDC fans and high-ISEER RACs; align star-label timelines with ICAP trajectories to avoid efficiency backsliding.
Finance first costs: enable OBF via DSM regulations, pilot pay-as-you-save for housing societies, and deploy risk-sharing facilities so lenders treat efficient cooling like priority retail credit.
Design for climate and income: require state cooling roadmaps to use the ECBC climate-zone tool and per-capita income data to tailor measures (e.g., ventilation-first in warm-humid low-income districts; envelope retrofits in composite/hot-dry middle-income cities).
Design-led solutions pay back many times over. They lower household energy bills, defer expensive grid upgrades, and create healthier indoor environments for those who cannot afford air-conditioners. For governments, every avoided megawatt of peak demand saves capital expenditure otherwise required for generation and transmission.
For the environment, the benefits are more enduring: fewer emissions, lower heat-island effects, and resilience for vulnerable communities who remain outside the reach of mechanical cooling. In short, design is the cheapest and most equitable route to decarbonising India’s residential cooling demand.
India will not air-condition its way out of the heat. It must design its way out first, and finance wisely where machines are still needed. Every square metre of reflective roof, every ventilated room, and every insulated wall is an emissions cut today—and a debt we do not pass to tomorrow.