Europe outpaces US in energy efficiency

Across Europe, countries are experimenting with policies to encourage homeowners, renters and landlords to make buildings more energy-efficient. They've been prodded by the European Union, which as part of its effort to fight climate change has set an ambitious goal to cut energy consumption in buildings 11% by 2020.

In the U.S., some companies such as Citigroup Inc. and a handful of states such as California have launched efforts to improve energy efficiency in buildings. But in general, the U.S. has been slower to devise policies to address the problem. The EU, meanwhile, has mandated that member states renew their building codes every five years and create standards to calculate the energy efficiency of buildings.

Another measure calls for all buildings to submit a report card, or "energy certificate," which can be shown to prospective buyers or renters. The hope is that grading buildings on their energy efficiency will spur landlords and owners to undertake renovations.