Be sure that information is copied accurately from utility bills, including start and end dates of the statement period, and that you are using actual meter readings as opposed to estimated readings whenever possible. Replace estimated meter readings with

Be sure that information is copied accurately from utility bills, including start and end dates of the statement period, and that you are using actual meter readings as opposed to estimated readings whenever possible. Replace estimated meter readings with actual meter readings once those statements are received. Exporting data inputs from Energy Star and graphing the utility data can help uncover data entry errors through visual comparison.