Rotary International

Boiler Plant Replacement

Boiler Plant Replacement - Evanston, IL


The new plant consists of five condensing boilers rated at 3,000 MBH each (total plant capacity of 15,000 MBH), with a thermal efficiency rating of up to 99%. The building was an excellent application for high efficiency condensing boiler technology because, as a heat pump system, the original hydronic heating system was designed to operate at low water temperatures.


Source Award
2008 Excellence in Engineering Award, ASHRAE Illinois Chapter
2009 Regional Technology Award, ASHRAE Region VI (second place)


  • At 15,000 MBH (450 boiler horsepower), One Rotary Center is home to one of the largest condensing boiler plants in the United States.
  • A new mechanical equipment penthouse was constructed on top of the building’s parking garage and immediately adjacent to the existing fourth floor main mechanical room. The existing electric boilers were demolished, and the heating and cooling systems were segregated and control schemes revised to operate in a more conventional manner.
  • More than 2,000 tons of greenhouse gas emissions were eliminated -- a reduction of 80% -- by using the condensing boiler plant instead of the old equipment combination of heat pumps and electric boilers.
  • Utility cost savings during the first season of operation were estimated at $127,000, based on an avoided electrical cost of $206,000 and an added natural gas cost of $79,000.