From their national headquarters in Oklahoma City, GWS has been making “green” happen since 1986. GWS engineers, consultants and inspectors offer extensive Building Science Services for new and existing, residential and commercial construction. With wide-ranging knowledge in energy efficiency and green building practices, GWS provides complete and impartial, third-party construction consultation. GWS is a national leader in Energy Star certifications with 38,000 homes certified and managed the certification of the first LEED home in the nation.