Knox Hall, located at Columbia affiliate Union Theological Seminary on 122nd Street and Broadway, utilizes four 2,000-foot deep geothermal wells. The geothermal wells, each eight inches in diameter, provide heating and cooling by drawing ground water from the earth. The wells eliminate the less efficient chillers associated with more traditional systems. By coupling the building's mechanical systems with earth's natural resources, the geothermal wells allow for the installation of a sustainable system design which benefits not only the University but the community as a whole. By using this "greener" system, the University projects energy savings of 50 to 60 percent.