Cooling in buildings

Tracking Clean Energy Progress

🕐 Last updated Wednesday, 13 March 2019

More efforts needed

Energy demand for cooling is the fastest growing end-use in buildings. Sales are rising three times faster than efficiency improvements, and 10 air conditioners will be sold every second over the next 30 years. To put cooling on track to meet the SDS target, minimum energy performance standards need to push markets to improve AC performance by more than 50% by 2030. This could cut CO2 emissions from space cooling in half while reducing local air pollution.


Average seasonal energy efficiency ratios of sales and stock to 2030

The efficiency of air conditioners is improving, but not nearly fast enough

	Residential - in use	Residential - sales	Non-residential - in use	Non-residential - sales
1990	2.47	2.75	2.38	2.67
1991	2.56	2.92	2.44	2.70
1992	2.66	3.13	2.52	2.87
1993	2.74	3.17	2.59	2.94
1994	2.82	3.18	2.65	3.00
1995	2.88	3.19	2.71	3.03
1996	2.92	3.15	2.75	3.04
1997	2.95	3.15	2.77	3.00
1998	2.98	3.20	2.80	3.15
1999	3.02	3.30	2.83	3.14
2000	3.06	3.29	2.86	3.10
2001	3.09	3.25	2.89	3.13
2002	3.13	3.30	2.92	3.14
2003	3.15	3.28	2.95	3.23
2004	3.18	3.37	2.98	3.28
2005	3.22	3.58	3.02	3.35
2006	3.27	3.74	3.08	3.55
2007	3.33	3.82	3.15	3.59
2008	3.40	4.00	3.22	3.67
2009	3.47	4.07	3.29	3.76
2010	3.56	4.13	3.36	3.83
2011	3.64	4.16	3.43	3.90
2012	3.70	4.10	3.49	3.92
2013	3.76	4.11	3.55	4.02
2014	3.82	4.15	3.61	4.13
2015	3.87	4.17	3.67	4.16
2016	3.93	4.17	3.74	4.22
2017	3.98	4.15	3.80	4.22
2018	4.03	4.24	3.86	4.35
2019	4.14	4.66	4.00	5.00
2020	4.23	4.82	4.13	5.23
2021	4.32	4.97	4.28	5.45
2022	4.42	5.11	4.43	5.67
2023	4.52	5.24	4.59	5.87
2024	4.62	5.38	4.76	6.06
2025	4.73	5.50	4.92	6.22
2026	4.85	5.62	5.09	6.37
2027	4.97	5.72	5.25	6.52
2028	5.09	5.83	5.42	6.65
2029	5.21	5.93	5.57	6.79
2030	5.34	6.04	5.73	6.93
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2018 was an exceptionally hot year in many parts of the world, with big impact on demand for cooling services. Final energy use for cooling is estimated to have increased by 5% globally in 2018, consuming around 2 100 TWh of electricity– or nearly as much as all the electricity consumed by G8 countries last year. More than 1.6 billion air-conditioning units are now in operation globally, making space cooling the leading driver of new energy demand in buildings.

In particular, air-conditioning demand in China has grown spectacularly over the last decade, reaching around one-third of the global air-conditioner stock as of 2017. There were nearly 350 million more units in use in China in 2017 than in 2007, and summer heat waves across China in 2018 only helped to push that number further. This rapid growth is now being mirrored in other emerging economies, particularly in Brazil, India, Indonesia and Mexico, who together now represent a market of around 115 million air-conditioning units.

The Kigali Amendment to the Montreal Protocol on hydrofluorocarbons and the subsequent Kigali Cooling Efficiency Programme (K-CEP) launched in 2017 are working closely with partners across multiple countries to promote major energy efficiency gains and sustainable cooling solutions, bringing together philanthropic foundations, technical experts, international organisations and other cooling partners.

The IEA also launched in 2018 the Kigali tracker under its Global Exchange Platform to work with countries and K-CEP partners to track information on energy efficiency, refrigerants, investments and policies.

In September, India released its Cooling Action Plan – the first of its kind in the world – that has put forth multiple proposed interventions to address cooling across multiple sectors. This Plan was released on the back of 2018 updates to India’s Seasonal Energy Efficiency Ratings (ISEER), which took effect in January 2018.

On the technology side, Carrier launched an air-conditioning unit in early 2018 with a seasonal energy efficiency ratio (SEER) of 12.3, three times the market average efficiency of residential air-conditioning unit sales in the United States in 2017. While these types of efficiency levels are still unlikely to reach the market in most countries, they illustrate the potential for cooling equipment to drastically improve performance levels.


Tracking progress

If improvements in the energy efficiency of cooling equipment continue to lag behind increases in sales, air-conditioning electricity demand could increase by as much as 60% globally by 2030 – 40% greater than the pace needed to match SDS targets.

Market trends suggest that substantial energy efficiency gains could be tapped into quickly. The average SEER of air-conditioning units sold in the fastest-growing markets, such as China and India, is typically around 4. Yet products available in those same markets – often at comparable prices – can have SEERs that are 50% to 70% better. Best available technologies are often twice as efficient, if not more.

Seasonal energy efficiency ratios of residential AC sales across key markets

The best-available cooling technologies are often more than twice as efficient as the average units sold.

	Average
        Europe	5.3
Japan	5.2
Korea	4.6
China	4.4
United States	4.2
Singapore	4.2
Canada	3.9
Australia	3.5
Thailand	3.3
India	3.2
Saudi Arabia	3.0
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To capture this potential, countries need to show stronger commitment to push forward higher performance standards for air-conditioning units, especially given that global air-conditioning stocks are expected to increase by as much as 80% by 2030.

Stronger effort is particularly needed to introduce and gradually increase minimum performance standards for air-conditioning units. Typical efficiencies of residential units sold in major cooling markets are not much better than minimum available products. The same is equally true of most non-residential cooling sales.


Breakdown of final energy demand for cooling in the SDS relative to 2000

Energy use from growing demand for ACs can be partially offset by energy efficiency and improved performance

	Energy change	Population	AC ownership	Cooling energy intensity	Climate	Equipment performance	Other energy efficiency
2000	336.8	83.6	153.1	327.6	-78.1	-130.4	-18.9
2001	385.3	93.2	180.0	248.1	26.1	-140.5	-21.7
2002	509.1	103.3	205.6	381.6	-6.0	-151.0	-24.4
2003	537.3	113.9	237.0	348.8	27.6	-163.1	-26.9
2004	607.2	124.8	273.5	449.3	-32.8	-177.1	-30.4
2005	711.2	136.2	319.6	452.1	32.3	-193.8	-35.3
2006	697.5	148.4	361.9	369.5	77.6	-219.9	-40.1
2007	788.2	161.3	414.3	488.8	18.9	-249.5	-45.7
2008	799.8	174.6	458.4	520.3	-19.5	-282.1	-51.9
2009	785.2	187.2	506.4	453.2	13.9	-316.6	-59.0
2010	951.5	199.7	554.8	501.5	116.2	-352.8	-67.9
2011	966.8	212.2	596.7	594.6	27.8	-389.3	-75.3
2012	1034.3	224.7	647.7	587.9	79.6	-421.6	-84.1
2013	1055.2	237.6	682.7	594.5	86.0	-450.3	-95.3
2014	1094.0	251.2	732.3	669.8	26.7	-480.2	-105.8
2015	1212.4	264.5	772.1	715.2	95.0	-512.3	-122.0
2016	1295.0	278.3	835.1	659.4	201.8	-544.0	-135.6
2017	1337.7	292.2	893.8	726.4	144.6	-576.2	-143.1
2018	1418.6	306.3	967.4	816.6	110.1	-613.4	-168.3
2025	1247.6	353.7	1258.9	686.5	120.8	-899.7	-272.4
2030	1217.1	430.6	1854.6	746.9	155.5	-1440.2	-530.3
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Improving air-conditioning equipment performance will be a major way to reduce the impact of growing energy demand for cooling.

Average efficiencies of new air-conditioning units sold would need to move from a SEER of around 4 today to 7 or higher in 2030 – a task that is not insurmountable but one that would require strong market signals and greater collaboration between countries.


Innovation

One notable development in 2018 is a newly announced collaborative effort by the IEA Technology Collaboration Programmes (TCPs) for Heat Pumping Technologies (HPT TCP) and Energy Storage through Energy Conservation (ECES TCP). Starting in 2019, this collaboration will seek to develop a prototype “Climate Comfort Box” that would deliver high efficiencies with flexible storage at affordable prices in order to deliver on ambitions for affordable heating and cooling under Mission Innovation.


The IEA’s new Innovation Tracking Framework identifies key long-term “technology innovation gaps” across the energy mix that need to be filled in order to meet long-term clean energy transition goals. Each innovation gap highlights where R&D investment and other efforts need improvement.

Explore the technology innovation gaps identified for cooling below:

Solar

Why is this RD&D challenge critical?

  • In conventional air conditioning systems the sensible load decreases the temperature to 100% relative humidity (RH). The latent load removes the moisture of the air while containing 100% RH. This usually results in temperature levels below thermal comfort, hence, the air needs to be reheated and this requires additional energy.
  • Humidity (or rather the latent heat the humidity contains) is responsible for a large share of the cooling demand in many countries.
  • SSCL systems with one vapour-compression system and one solid/liquid desiccant wheel could address this as it does not require any reheating.

Key RD&D focus areas over the next 5 years

  • Further R&D on optimal systems; materials for solid/liquid desiccants.
  • Further innovations needed to improve efficiency and Seasonal Energy Efficiency Ratios (SEERs).

Why is this RD&D challenge critical?

  • This type of system can operate with low grade solar energy (i.e. lower temperatures). Desiccants can dry the air without first cooling it below its dew point. When the desiccant is loaded with water, heat is supplied so as to take it back to the "natural" state and hence air conditioning is provided.
  • Liquid desiccant cooling is suited for solar cooling as it can operate at low temperatures (50-90 C), and allows for high density and less energy storage in the concentrated desiccant.

Key RD&D focus areas over the next 5 years

  • Liquid desiccant cooling systems that use liquid water-lithium as sorption materials.
  • Compared to solid desiccant this can achieve a higher air dehumidification at the same driving temperature.
  • Reduce costs.

Explore all 100+ innovation gaps across 38 key technologies and sectors here.