Cooling in buildings

Tracking Clean Energy Progress

🕐 Last updated Wednesday, 23 May 2018

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
2000	3.05	3.20	2.86	3.13
2001	3.08	3.19	2.89	3.20
2002	3.11	3.24	2.91	3.18
2003	3.14	3.37	2.94	3.23
2004	3.17	3.43	2.98	3.26
2005	3.22	3.60	3.01	3.34
2006	3.29	3.78	3.07	3.55
2007	3.36	3.85	3.15	3.60
2008	3.44	3.95	3.22	3.70
2009	3.53	4.05	3.30	3.82
2010	3.62	4.06	3.37	3.85
2011	3.71	4.11	3.44	3.95
2012	3.78	4.12	3.50	3.96
2013	3.85	4.11	3.55	4.06
2014	3.91	4.11	3.61	4.16
2015	3.96	4.11	3.67	4.19
2016	4.01	4.14	3.73	4.24
2017	4.05	4.16	3.80	4.26
2020	4.38	5.16	4.23	5.60
2025	5.22	6.11	5.31	6.87
2030	6.15	6.91	6.38	7.78
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Space cooling is the fastest growing end-use in buildings, having increased by 3.3% a year since 2010. With nearly 1.6 billion air-conditioning units in operation globally, cooling represented roughly 6% of total final energy consumption in buildings in 2017 and around 20% of buildings sector electricity use.

The number of air-conditioners rose 50% over the last decade, turning space cooling into the leading driver of new energy demand in buildings.

In particular, air-conditioning demand has grown spectacularly in China over the last decade, reaching around one-third of the global air-conditioner stock in 2017. There were nearly 350 million more units in use in China in 2017 than in 2007. As a result, air-conditioning units (excluding household fans) consumed around 1 900 TWh of electricity demand globally in 2017, more than all the electricity produced in Japan and Korea. This rapid growth will continue as countries with hot climates, such as Brazil, India, Indonesia and Mexico, follow in China’s footsteps.

The Kigali Amendment to the Montreal Protocol on hydrofluorocarbons and the subsequent Kigali Cooling Efficiency Programme (K-CEP) launched in 2017 provide a key opportunity to promote major energy efficiency gains and sustainable cooling solutions, bringing together philanthropic foundations, technical experts, international organisations and other cooling partners.

K-CEP funders have committed USD 52 million to help developing countries transition to energy-efficient, climate-friendly and affordable cooling solutions – the largest single philanthropic commitment ever made to advance energy efficiency in the developing world.

Starting in 2018, the IEA will also host 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.

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	0	0	0	0	0	0	0
2001	44.8369135	9.114945636	26.48799467	-78.56566902	96.55787847	-9.292672736	0.534436476
2002	166.3555718	18.69529136	52.4105581	36.55403377	66.42451664	-19.15869047	11.42986235
2003	186.4735739	28.79326858	83.78245623	52.17855583	92.3083893	-31.27785946	-39.31123661
2004	256.3039911	39.09252222	120.04189	112.6320022	36.75405021	-45.45951837	-6.756955128
2005	352.7035758	49.95701628	165.9826805	139.7986723	99.3782581	-63.39050326	-39.02254815
2006	342.0753934	61.52126645	207.0450188	-8.324873573	133.3611085	-89.09819837	37.57107149
2007	432.9591937	73.67169848	259.0952274	110.0199545	89.14367675	-120.8330207	21.86165732
2008	441.3913355	86.28391747	302.8825536	202.8588559	47.00796114	-155.423047	-42.21890561
2009	422.5410499	98.18390523	351.2171702	149.9594609	75.95464706	-191.4746092	-61.29952432
2010	586.7363233	110.0635094	399.9041515	265.7221746	181.5795043	-226.8327713	-143.7002453
2011	591.2024141	121.8178811	442.2548103	336.6332578	97.83103397	-261.8354601	-145.499109
2012	652.878463	133.5558398	493.4276113	320.9777858	144.7587277	-293.200131	-146.6413705
2013	671.2009829	145.7014189	529.2675571	316.706321	147.9048145	-321.1509863	-147.2281423
2014	700.8068816	158.4294652	579.034047	363.1625632	95.79592698	-347.90793	-147.7071908
2015	808.6000507	170.8185637	619.8677102	390.7339135	156.2444858	-375.4596313	-153.6049912
2016	944.5026317	183.9085398	682.727409	384.6743145	255.3717444	-403.1331381	-159.0462379
2017	962.9274365	197.2414516	742.8868981	413.6206778	200.735331	-430.7178884	-160.8390336
2025	827.1027206	255.3320582	1084.926935	293.0121158	195.9194582	-746.4089221	-255.678925
2030	816.8886331	330.8367718	1620.788728	315.2711512	232.1030813	-1261.779136	-420.3319636
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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 2017 is a proposed collaborative effort by the IEA Technology Collaboration Programmes (TCPs) for Heat Pumping Technologies (HPT TCP) and Energy Storage through Energy Conservation (ECES TCP). This collaboration seeks 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.