Solving the air conditioning paradox: Dan Hamza-Goodacre, ClimateWorks

Reading time: 2 minutes
6 April 2016

Dan Hamza-Goodacre, Director of Energy Efficiency at ClimateWorks, talks about solving the challenge of the world’s growing demand for air conditioning in urban areas efficiently in a way that is low carbon – and energy efficientThis is part of The Climate Group's project Home2025.

As urban populations swell like never before in history, we are building more property and infrastructure and using more energy.

More time spent indoors in these ‘urban heat islands’ is driving an explosion of air-conditioning, fueled primarily by high-carbon energy and leaking refrigerants with as much as 12,000 times the global warming potential of carbon dioxide.

Air conditioning (AC) is exacerbating the cooling problem it is designed to solve. This is a collective ‘Darwin Award’ candidate on a huge scale! More energy efficient, low hydrofluorocarbon (HFC), air conditioning units certainly need to dominate the market.

By 2030, in India alone there are expected to be an additional 112 million AC units (up from just 4 million in 2010) consuming 150 gigawatts of energy, which is equivalent to 300 new power plants. And yet the most efficient air conditioning models sold in India are 200% less efficient than the most efficient models currently available.

Minimum efficiency standards and labels, as well as financial incentives can speed and scale the uptake of more sustainable AC units.

But we must look beyond more sustainable AC units in order to solve the air conditioning paradox.  


The place to start is building design and adaptation. Natural ventilation, shading, evaporative cooling, and building material can all cool space using less energy and carbon.

A 2008 study conducted in Mexico analyzed the potential of energy savings from natural ventilation for residential homes, and found the average aggregated savings potential using ventilation was 4.2 terawatt-hours (equivalent to 54.4% of the Mexican electric cooling demand that year).

The study also estimated the average economic saving at US$900 million and average annual carbon savings of 2 million tons of carbon dioxide.

In addition, simple adaptations such as painting rooftops white can save significant amounts of energy and carbon by reflecting heat away from buildings. Cool roofs, painted with reflective (white) paint will stay a staggering 31 degrees Celsius cooler compared to a gray roof.

In parallel with building design and adaption, reconsideration of the perception of comfortable indoor temperatures can also result in more sustainable space cooling.

‘Thermal adaptive comfort’ is the ability of humans to adapt to, and even prefer, a wide range of thermal conditions if the perceived difference between indoor and outdoor temperature aligns with the external climate, and if the occupant has control of indoor conditions.

Put simply, being able to open a window on a hot summer’s day makes one more accepting of higher indoor air temperatures, and thus reduces the level of AC needed.


Cooling the space where we work, rest, play, and worship is critical for human prosperity.

Going beyond air conditioning units to building design and adaption will require better building codes and financial incentives to retrofit. Governments can and must do more.

But businesses also need to act by investing in low carbon innovation and by promoting the value of more sustainable appliances and property. And consumers need to take practical action to adapt to temperature ranges.

Space cooling can make economic and climate sense. Let’s make Darwin proud.

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