Portfolio Manager, EPA's (Environmental Protection Agency) on-line energy rating system for commercial buildings, now includes greenhouse gas emission factors. The updated ratings show that Energy Star buildings, which use an average of 35 percent less energy than typical buildings, also emit 35 percent less carbon dioxide into the atmosphere.

The emissions factors for carbon dioxide (CO2) are from EPA's Emissions & Generation Resource Integrated Database (eGRID) and are consistent with those used by major greenhouse gas reporting protocols. With the integration of eGRID into EPA's Portfolio Manager, businesses can see how the CO2 emissions of their buildings compare to others in their same region and across the country, reveals the organization’s press release. This allows organizations to assess and address the climate change impact of their buildings according to standardized protocols, prioritize energy efficiency improvements, and lessen the impact on the environment.

For example, a look at a typical office building in the New England region shows that the building contributes 20 pounds of CO2 per square foot. An Energy Star office building in this region contributes just 15 pounds per square foot, a reduction of at least 25 percent.