Before a renovation that began 11 years ago, the 139-year-old St. Patrick's Cathedral in New York was running on city steam, and its mechanical systems were in need of an upgrade. Now, the cathedral has a geo-exchange(geothermal) heat pump system that meets the cathedral's heating and cooling demands. The deepest of the system's 10 wells is 2,220 ft (670.5 m) deep under St. Patrick's—more than 6.5 times as deep as the cathedral's 339-foot (103.3 m) spires.