Across the Gulf, energy-thirsty air conditioning units chug along throughout the day.
It is estimated they'll be switched on in homes at least 250 days a year – and in most offices and malls, they'll run every day of the year.
They make life in the world's hottest region bearable and are essential for the economy to function.
But the need to stay cool requires the use of ever-increasing amounts of power, with climate change and extreme weather putting sources of energy under greater scrutiny.
AC power consumption increased five-fold in the Middle East between 1990 and 2016, the World Bank said. With much of the electricity in the region generated by burning fossil fuels, the need to keep people cool contributes to the warming of the planet.
"Electricity consumption in the GCC is among the highest in the world," said Prof Moncef Krarti, of the civil, environmental and architectural department at the University of Boulder, Colorado.
He has analysed electricity consumption in all of the Gulf nations and has found that air conditioning typically accounts for between 65 and 70 per cent of the electricity used in homes.
Prof Krarti and his colleagues calculated that upgrading Saudi Arabia’s stock of old window AC units (of which there are 18 million) and split-system AC units (which have an indoor and an outdoor component) would cut AC electricity consumption by about 40 per cent.
This is equal to 33 terawatt hours of electricity a year. A TWh is the amount of energy needed to run a device for an hour that consumes one trillion watts when it is operating.
Given that 1 TWh can cool about 500,000 homes for one year or fully power 70,000 homes for a year, the savings are potentially significant.
The UAE has had minimum performance standards for new air conditioners for more than a decade, but buildings still account for nearly 90 per cent of electricity used, Prof Krarti’s research showed.
Retrofitting buildings in the UAE to make them more energy efficient, including by upgrading AC units, could cut energy consumption by 7.55 TWh a year and reduce annual carbon emissions by 4.5 million tonnes.
Other Gulf nations offer similar potential for electricity savings through AC upgrades and other measures, including Oman (0.96 TWh reduction), Bahrain (0.32 TWh reduction) and Qatar (11 TWh reduction).
Retrofit, retrofit, retrofit
Tariq Al Ghussein, chief executive of Taqeef, an AC company that operates in several countries including the UAE, said the latest units offered a large improvement on older devices.
He said a current non-ducted unit (a type of AC unit normally used to cool individual rooms) consumed 54 per cent less power than a 2011 model under the same test conditions. "New AC units achieve significantly higher energy efficiency compared to older systems," he said.
An important metric for AC units is the Energy Efficiency Ratio (EER). Older devices may have an EER of about 8.5, while it may be about 13 for newer pieces of equipment.
Countries including the UAE, Saudi Arabia and Kuwait have minimum EER standards for AC units in new homes, but existing devices may be much less efficient.
Electricity is often heavily subsidised, so there may be little incentive for consumers to replace older AC units or to set a higher thermostat temperature.
"Because of the subsidy, some GCC countries have electricity cost of less than one cent per kilowatt hour, like in Kuwait, which makes any energy efficiency measure not very cost effective," Prof Krarti said.
"In the UAE and Saudi Arabia now, with the price reform, it is cost effective, and there’s actually a programme within Saudi Arabia to encourage homeowners to replace their AC systems," he added.
The cost of electricity to consumers in Saudi Arabia, before price reforms began in late 2015, was 0.05 Saudi riyals for every KWh (for the first 6,000 KWh used a month). By 2018, the cost had risen to 0.18 Saudi riyals.
Last year, the average cost of a KWh in Saudi Arabia was 0.15 riyals, figures released by commodity analysts Intratec showed.
The Dubai Electricity and Water Authority said a KWh cost Dh0.23 for the first 2,000 used, with the price rising to Dh0.28 per KWh once 6,000 have been used.
There has been an international push to phase-out fossil-fuel subsidies, including those that keep electricity prices artificially low. At the Cop28 climate change summit in Dubai last year, the Netherlands launched what it described as an international coalition to end those subsidies.
In the UAE and other parts of the Gulf, Energy Service Companies may finance improvements in energy efficiency, such as the upgrading of AC units, and be paid out of the savings that result.
The authorities in some Gulf states, including Saudi Arabia, have offered financial support to encourage people to replace older AC units with more efficient devices.
Cooling dry air v humid air
Many air conditioners are vapour compression units, which force a refrigerant gas into the unit’s condenser coil, where the refrigerant turns into a liquid. The refrigerant is then sent into the part of the AC unit situated inside, where it evaporates, a process that absorbs heat from the indoor coil, which cools.
Another type of air conditioner, an evaporative cooler, does not contain a refrigerant, but instead makes use of the fact water absorbs large amounts of heat when it evaporates.
Research carried out by Prof Krarti, in collaboration with King Abdullah University of Science and Technology in Thuwal, Saudi Arabia, found that using hybrid AC systems that combine vapour compression units with evaporative coolers in the coastal city of Jeddah could reduce power consumption for air conditioning by 48 per cent.
In a house in Riyadh, which is inland and has a drier climate, energy consumption could be cut by more than 90 per cent, the research found.
"In Dubai, there’s other options. In a large community, we could use district cooling, which is even more efficient than individual cooling systems for each building," Prof Krarti said.
As well as replacing outmoded AC units with newer models, analysts recommend regular servicing, because without that, efficiency could fall away.
Cutting energy use from air conditioning is not just about the AC units: building design and materials also influence how much power is consumed. A recent University of Sharjah study found that thermal insulation, ventilation and shading could reduce electricity demand by at least 40 per cent.
Electricity bills and rising temperatures
As the climate warms, a concern is that the energy consumed by air conditioners will increase. Prof Krarti said a 1°C increase in temperature results in about 10 per cent greater AC energy consumption to maintain the same temperature within a typical home in the Gulf.
"The electricity bill is not necessarily going to increase due to climate change if highly efficient AC products with the latest technology are prioritised," Mr Al Ghussein said.
"As long as outdated, inefficient AC units are replaced with modern, energy-efficient models, rising temperatures can be countered without exorbitant increases in utility costs."
Nevertheless, increases in air conditioning demand stemming from higher temperatures are forecast to put a strain on electricity grids in some parts of the world.
"We’ve seen in some countries, particularly the US, if everybody turns on the AC at the same time, you get such a surge of electricity use it can put the power grid under strain," said Bob Ward, policy and communications director at the Grantham Research Institute on Climate Change and the Environment, part of the London School of Economics.
A 2022 study released in the American Geophysical Union’s journal Earth's Future found that if average temperatures reached 2°C above pre-industrial levels, air conditioning demand could surge by 13 per cent, risking extended power cuts during peak summer heat.
Globally, energy use for air conditioning has been forecast by the World Bank to triple by 2050, primarily as a result of rising living standards and population increases. Demand in the tropics and subtropics, including in nations such as India and China, is set to increase five-fold.
Installing more efficient devices may reduce the extent to which power demand for air conditioning increases, but behavioural change may also play a part. Mr Al Ghussein said energy consumption could be limited by setting the AC thermostat at 24°C, rather than a lower temperature.
The authorities in parts of the world including Japan, India and California have tried to encourage people to set AC units at between 24°C and 28°C, by making recommendations or by introducing regulations on default settings.
