Rhodes State Tower

Managing pressure in high rise applications

Simple payback in 1 year

One tall order
  • When a high-rise exceeds 15 stories, controlling the building pressure is much more challenging and complex
  • The Rhodes Tower experienced severe building pressure problems in winter that caused whistling elevator shafts, comfort issues and significant drafts
  • The building pressure algorithms had to coexist with CO2 demand ventilation control strategies
  • The stack effect pressures on elevator and smoke control shafts were uncontrolled
  • Night-time/weekend set-back strategies needed to be integrated

Vertical integration
  • Pathian® provided project management, engineering and commissioning services
  • Installed building pressure sensors in the lobby, 41st floor and two additional sensors at intermediate elevations
  • Installed VFD’s on existing constant volume return fans
  • Replaced system controllers on 8 large custom AHU’s
  • Reprogrammed AHU’s to Pathian control strategy
  • Implemented Pathian Analytics software to track, evaluate and sustain optimal equipment performance

Top to bottom improvements
  • Increased comfort level across all 41 floors
  • Total project cost: $150,000
  • Utility Rebate (Custom/Prescriptive): $38,400
  • Estimated project savings:
    • Electric (806,400 kWh/yr @ $0.0969 per kWh) $78,140
    • Natural Gas (6368 MCF/yr @ $4.61 per MCF) $29,674
  • Simple payback: 1.03 years
  • Building Energy Star certifications: 2018, 2019, 2020, 2023

Other industries



Columbus, Ohio

Building Facts

Office building
Built in 1974
1,200,000 sf
41 stories (629 ft)
4000+ employees

ENERGY STAR® certified