According to the International Energy Agency (IEA), deploying energy efficiency policies could reduce energy bills for consumers by more than $500 billion per year. Efficiency gains alone could allow the world to extract twice as much economic value from the energy it uses compared to today. The report sets out a vision for 2040 with 60% more building space and 20% more people, and double global GDP while using only marginally more energy than today and cutting greenhouse gas emissions by 12%. Delivering this vision requires an immediate step up in policy action: countries would need to continue to push up the efficiency of both cars and trucks, building on the progress made in recent years. Another priority is the efficiency of air conditioners, as highlighted in the IEA’s recent report The Future of Cooling. This demonstrated that air conditioners could be twice as efficient as they are today with the right policies in place. Global investment in energy efficiency will need to rise significantly, but this investment will pay back threefold through energy savings alone.