Washington National Cathedral

Comprehensive HVAC system upgrade

  • Owner:
    Protestant Episcopal Cathedral Foundation
  • Location:
    Washington, DC
  • Size:
    50,000 sq ft
  • Approach:
    Design Build
  • Scope:
    HVAC, Plumbing, Piping, Temperature Controls

Washington National Cathedral was first air conditioned in the mid-1970s by RM Thornton Mechanical who installed large air handlers to bring in air from the outside and recycle air from the interior, but the cathedral did not have the resources at the time to add the pipes and chiller to cool the cathedral’s vast interior. In 2000, several donors stepped forward donating the necessary funds needed to complete the job, and RM Thornton was once again called on to provide all mechanical services.

The work included installing air handlers each capable of cooling a 50,000 sq ft office building, a chiller plant that uses ice tanks to cool water at night, a complete chilled water and associated piping system from support buildings under the Cathedral and through its crypts, and cooling towers built unobtrusively down the hill from the Cathedral. New features such as digital controls were also added.

In this Design Build project, the foreman and crew determined the entire piping system while working in extremely challenging work conditions. The results were amazing and the temperature continues to remain at a constant 72 degrees in the summer.