OAKLAND, Calif. — The U.S. Environmental Protection Agency has added greenhouse gas emissions factors to its online energy rating tool for commercial buildings.

This allows building owners and managers to compare the amount of emissions their buildings are likely producing compared to others in the same area.

The tool, Portfolio Manager, already helps building managers and owners streamline energy and water data and track key factors, such as consumption, performance and costs. For instance, owners can benchmark their facilities against past performance and track multiple energy and water meters.

The EPA added the data for carbon dioxide emissions from its Emissions and Generation Resource Integrated Database. This allows users to compare the emissions generated from their buildings with other buildings in the same area.

"This consistency makes it easier for organizations to quantify their carbon inventories and provides a transparent corporate accounting, inventory, and reporting method," the EPA said.

The figures relying heavily on the Energy Star designation for the comparison figures. A typical office on the Hawaiian island of Oahu, for instance, generates 35 pounds of carbon dioxide emissions per square foot while an Energy Star office building in the same area produces 26 pounds of carbon dioxide per square foot.