How AC Temperature Limits Can Help Save Energy

"We have decided… to bring uniformity to air conditioning use and help reduce excessive power consumption due to extremely low cooling settings," the former Haryana CM informed the media.

The announcement was met with criticism on the grounds that the government is interfering in people’s personal choices; supporters on the other hand say it might not be a bad idea, given how much electricity is consumed by room air conditioners in the fraction of India’s households that can afford them, and given how consumption is only going to increase. Among AC-owning households in India, only 40% run ACs at a temperature setting of 24°C or above.

If ACs are set at 20°C and above instead of 16°C, not only can consumers save on power bills but it also spares energy for the most marginalised in a country where the electric fans used by the majority together consume only slightly lower electricity than the air conditioning used by just around 7-9% residential consumers.

Several countries have already issued guidelines or set similar rules for ACs and thermostats. With heat waves surging outdoors, subjecting the body to fan-first cooling in tandem with air conditioning might be a better approach than relying on ACs set at the lowest 16°C to bring down the body’s temperature. More energy-efficient fans, better building design (measures like cool roofs), sustainable construction material, and incentives to opt for the most energy-efficient ACs will all be required to further achieve the goal of energy savings.

In this connection, note that India has pledged to reduce the emissions intensity of its gross domestic product by 45% by 2030 as part of its long-term climate plan.

Power saving mode

Between 2019 and 2023, India's hourly electricity demand on a high-temperature day in June (above 36°C temperature) increased on average by about 28%, caused largely by increased ownership of air conditioners and similar appliances. Total connected load in India due to air conditioning is estimated to be about 200 GW by 2030. For context, India's total electricity installed capacity at present is 475 GW.

Globally, the sale and use of air conditioning has grown exponentially. The International Energy Agency estimated that annual sales nearly quadrupled to 135 million units between 1990 and 2016. Roughly 2 billion air conditioning units are now in operation around the world, of which residential units make up 70%.

India has just about 7-9% penetration of air conditioning in the residential sector as of 2019. "This is anticipated to rise to 21% and 40% in 2027-28 and 2037-38 respectively," the government's first ever Cooling Action Plan had stated in 2019. Rapid urbanisation and electrification, construction boom, a growing middle class, decreasing room air conditioner prices, rising temperatures, and extreme heat events are all expected to contribute to this future AC boom.

Source: India Cooling Action Plan

Context and concerns

In 2018, India's Bureau of Energy Efficiency (BEE) recommended an optimum temperature setting for air conditioners, but only for major commercial establishments. It recommended a default setting of 24°C, but the user could adjust it manually. It reasoned that since the normal human body temperature is 37°C, temperatures up to 25°C are quite comfortable and anything lower than that was a waste of energy.

"...by increase in temperature of room by 1 degree Celsius, we can save about 6 per cent of electricity," it estimated. The overall potential for energy conservation through such measures was estimated to the tune of 20 billion units (worth Rs 10,000 crore) annually.

"If about half the consumers adopt such recommendations, this would result in about 10 billion units of electricity, which is equivalent to a reduction of 8.2 million tonne of CO2 per year," BEE estimated.

In 2020, it mandated a default setting of 24°C for all room air conditioners covered under the ambit of the BEE star-labelling programme.

In the global context, countries like Japan and the US have already put in regulations for the functioning of air conditioners. Japan introduced a default setting for ACs at 28°C. In the US, states like California have enforced norms that prevent the lowering of AC below 26°C. In 2022, Italy attempted to cap AC lower limits at 27°C, including a provision to levy fines. In 2018, China advocated that the thermostat of air conditioners should be set no less than 26°C in summer and no higher than 20°C in winter to save energy and resources.

India’s latest move to ensure that ACs cannot be set below 20°C and above 28°C was met with concerns and some uproar about infringement on people’s personal choices. But Shyamasis Das of the Delhi-based Centre for Social and Economic Progress believes that such actions for behavioural change are necessary to avoid wasteful electricity consumption.

“From a health point-of-view, if the outdoor temperature is 45°C and one suddenly steps into a room with 16°C, your body experiences thermal shock. So, the indoor temperature should not be drastically different from outdoors,” said Das.

The fan-first approach

The use of air conditioning to address exposure to heat is undoubtedly effective. However, ACs are expensive, require maintenance, consume more electricity, and are inaccessible to the most marginalized. With heat waves surging outdoors, subjecting the body to fan-first cooling in tandem with air conditioning might be a better approach than relying on ACs set at the lowest 16°C to bring down the body’s temperature.

In order to reduce our over-reliance on them and reduce costs, a recent paper by Australian researchers suggests using fans in tandem with air conditioners set at about 27°C.

“Fans can increase comfort, reduce cardiovascular strain, and reduce the rise in core temperature. They increase heat loss through convection when air temperature is lower than skin temperature and facilitate the evaporation of sweat or water applied to the skin surface under high humidity conditions,” the paper stated.

“Using electric fans first means that thermostats can be set to start cooling at higher temperatures (eg, ~27°C, as opposed to ~23°C). Thus on warm days, air conditioning units are on for shorter periods – if at all – without reducing thermal comfort or cooling of the body,” it stated.

Even a 2021 Lancet paper found that forcing air across the skin with devices such as electric fans has a 10–50-times lower electricity requirement and cost than cooling surrounding air with air conditioning.

But in India, only 20% always use a ceiling fan with AC.

“Due to their sheer volume, the total annual energy consumption of fans is currently only slightly lower than the total annual energy consumption of room air conditioners in India. Despite a rise in the penetration of room air conditioners in households, a significant portion of the population will still not be able to afford air conditioning in the next two decades and will continue to rely on natural ventilation and fan-assisted ventilation for thermal comfort. Hence, fan should be a key appliance to focus on from an energy efficiency lens,” the Cooling Action Plan had said.

The government also has a mandatory star rating system for ceiling fans since 2022. But star-rated fans are expensive and not easily available in the market. Only 3% of Indian households use energy efficient ceiling fans, which often entail a higher upfront cost but consume 50% less energy than conventional models. If they become more common, that could also be a measure to save energy further.

Not a silver bullet

Aditya Chunekar, fellow at Prayas Energy Group, called the decision to regulate AC temperatures sensible but said that its implications on energy savings and efficiency are likely to be small.

“There are many other things that the government can do such as enforcing building codes to ensure that all the buildings meet particular design standards, promoting research on alternative cooling technologies, giving incentives to manufacturers so that there is an economic case for them to produce more efficient ACs…,” said Chunekar. “This could also involve a public procurement programme, which mandates only energy-efficient air conditioners, or having some kind of exchange programme where old ACs are taken back and some rebate given on new ACs. Currently, all ACs have a GST of 28%. There can be a mechanism where more efficient ACs are taxed less, say, 12%. So, one is what is called the stick approach, where you tighten the regulations and the other is the carrot approach, which are these incentives. Both are needed.”

India has five ‘star ratings’ for ACs, with one star denoting least efficient and five star denoting most efficient. India produces (and therefore uses) most ACs in the 1 to 3 star categories, but the share of 4 and 5 star ACs is slowly increasing.

Revising the existing star rating system and making it more stringent for ACs could be another step towards energy efficiency. A recent working paper by University of California-Berkeley's Goldman School of Public Policy recommends that the most stringent 5 star rating of today should be the starting point or ‘1 star’ by 2027 in India. It states that 600+ AC models (20% of the models offered in the market) already exceed this level. Thus, efficiency norms should be progressively made more stringent going forward. Researchers expect that this move will reduce peak demand by over 60 GW by 2035, avoid Rs 7.5 trillion in generation and grid investments, and deliver up to Rs 2.2 trillion in net consumer savings.

“Of course, this move to regulate AC temperatures is not a silver bullet or magic wand,” said Das of CSEP. “Climate action does not work that way. It is one in a number of things that need to be done at the policy level in combination.”

IndiaSpend wrote to the Ministry of Power and Bureau of Energy Efficiency with questions on the next steps the government is taking in this matter, when a formal notification will be out, whether it is also planning to re-look into the star rating system for electrical appliances and sustainable construction norms. This story will be updated when we receive a response.

As India grapples with intensifying heatwaves and a rapidly increasing demand for air conditioning, policy decisions like these are important. If implemented, this regulation might be a critical step for energy savings which also leaves room for those who cannot afford air conditioning.

(Kawinkumar B and Kashish Kapoor, interns with IndiaSpend, contributed to this report)

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