The ABC’s of HVAC Commissioning for Historic Buildings

By Spencer Rioux, Project Manager and Partner, 360 Engineering

Quality control lives at the heart of every successful historic renovation, guiding decisions from initial assessment through final construction. As buildings are evaluated for continued public use, each phase—design, preservation, and system integration—demands careful oversight. Balancing historic integrity with modern performance, quality control ensures that every step of the process protects the past while delivering a structure built to serve the future.

Among the most important layers of quality control is HVAC commissioning, the systematic process of verifying and documenting that heating, ventilation, and air conditioning systems are designed, installed, tested, and operating according to the owner’s requirements and industry standards.  Older buildings typically weren’t designed or built to accommodate the physical scale and capacity of a modern HVAC system and are at risk of becoming damaged if a new HVAC system isn’t integrated carefully and correctly.

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Historic buildings present unique challenges that make commissioning critical:

1. Preservation of Architectural Integrity
   HVAC systems must be integrated without damaging or interfering with historic features. The Commissioning agent works alongside the design team (architects and engineers) to ensure minimal intrusion of ducts, piping, and equipment into the historic fabric.
2. Energy Efficiency in Older Structures
   Historic buildings often have poor insulation and irregular layouts. Commissioning helps optimize system performance to reduce energy waste while maintaining comfort.
3. Humidity and Temperature Control for Preservation
   Improper HVAC operation can lead to moisture issues, accelerating deterioration of wood, plaster, and artifacts. Commissioning ensures precise environmental control to protect historic materials.
4. Complex Retrofits
   Older buildings may have structural limitations and outdated infrastructure. Commissioning verifies that retrofitted systems work safely and effectively within these constraints.
5. Compliance and Documentation
   Many historic projects require adherence to preservation standards and sustainability certifications. Commissioning provides the necessary documentation for compliance.

An historic building in Loveland, Colorado recently completed a successful renovation with the use of commissioning.  The city’s Pulliam Community Building first opened in 1938 and became a venue for community events, dances, theater productions, and even housed City Council meetings.   After falling into disrepair and closing in 2010 due to code compliance issues, Loveland residents rallied to preserve and restore the building, recognizing its historical and cultural significance.  The primary renovation effort included full MEP upgrades along with architectural finishes throughout the building.

The recent renovation honors the building’s rich history while equipping it with modern systems and amenities for renewed community use. The primary objective of the project was to reopen the building as an assembly space, preserving its architectural integrity while upgrading infrastructure to meet current codes.

One of the most significant engineering challenges was retrofitting the mechanical systems within a historic structure with limited ceiling space (or none). Energy recovery units were added to address the ventilation requirements of modern codes, particularly in assembly areas that previously had no mechanical ventilation. These units supply fresh air to the basement meeting hall, first-floor support areas, and second-floor offices. Louvers were integrated into existing window openings, and a Variable Refrigerant Flow (VRF) system was installed to provide heating and cooling to the majority of the building, allowing for minimal ductwork and more discreet piping routes, preserving the building's historical features.

The auditorium, which spans the first and second floors, is now served by two large rooftop units situated in a new mechanical yard behind the building. Air distribution was redesigned for better efficiency and occupant comfort: previously reliant on high-mounted stage grilles, the new system uses exposed ductwork along the exterior walls. On the first floor, ducts were routed between the concrete structure, while on the second floor, spiral ducts were mounted on the wall and coordinated with structural and fire protection systems.

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The success of the design and construction was supported through a commissioning process, which typically involves:

• Design review: Ensuring plans meet performance and efficiency goals, as well as constructability and ongoing maintenance considerations.
• Installation checks: Confirming equipment and controls are installed correctly.
• Functional testing: Verifying systems operate as intended under various conditions.
• Documentation and training: Providing manuals and educating building operators.

The Pulliam Building reflects the community’s dedication to preserving Loveland’s heritage while breathing new life into one of its most iconic landmarks. The Pulliam Building now stands ready once again to host the community it has long served.

360 Engineering is a full-service mechanical engineering firm working on projects of all sizes across the U.S., including historic building renovations.  More information regarding 360 Engineering is available at www. 360eng.com