The review of policies being implemented in China, the EU, India and the US presented in this report has also identified some key challenges that we must address if we are going to realize the mitigation potential of the building sector. Chief among these is the need to improve our monitoring of the impact that our policies are having. Lack of measured and verifiable data on the influence of policies on building energy performance currently hampers our ability to assess and continuously improve their effectiveness. Development of energy performance requirements for existing building renovation is also necessary. The report also shows that despite effective ‘best-practice’ policies being implemented in each region, we are yet to achieve a mainstream adoption. Today’s best-practice policies are also not necessarily ambitious enough in setting energy performance targets necessary to reduce energy demands and associated GHG emissions at the rate and magnitude necessary to reduce our sector’s overall impact on climate change