Making buildings more energy efficient is a cost-effective way to reduce greenhouse gas emissions, particularly since existing buildings account for 24% of world CO2 emissions, according to a new report published by the International Energy Agency. “With surging energy consumption, high energy prices and raising CO2 emissions, the imperative to improve energy efficiency is stronger than ever,” IEA Executive Director Nobuo Tanaka said. “On this road to a sustainable energy future, action in the building sector can play a key role,” added Tanaka. The IEA reported that existing buildings are responsible for more than 40% of the world’s total primary energy consumption. In collaboration with Agence Francaise de Developpement (AFD), the IEA assessed existing policies in measures to improve energy efficiency in existing residential buildings in Japan, the US, France, Germany and the UK. It pointed out that in all cases there were several market barriers inhibiting increased energy efficiency in residential buildings, such as difficulties in accessing capital, low priority of energy issues and different incentives between investors and energy end users, such as between a landlord and a tenant. “Our study identifies many effective policies to help overcome financial barriers to increased energy efficiency in buildings”, Tanaka said, adding that “more systematic data collection is essential to allow policy makers to understand trends and design the most appropriate policy packages to tackle these issues”.