Commercial HVAC systems must comply with ASHRAE Standard 62.1: Ventilation for Acceptable Indoor Air Quality, which establishes minimum ventilation requirements to support acceptable IAQ. | Photo Credit (all): Courtesy of Fellowes
By Jason Jones, Director of Air Quality Management, Fellowes
If you want to reduce energy waste in a commercial building, few systems offer greater opportunity than ventilation. HVAC accounts for 39% of a building’s total energy use and a significant portion of that goes toward conditioning outdoor air that must be continuously brought inside to meet indoor air quality (IAQ) requirements. It’s a substantial operational expense, and one often accompanied by unnecessary energy use and embodied carbon impacts. For facilities pursuing aggressive sustainability targets or just looking for ways to cut their energy bill, ventilation loads can undermine progress toward decarbonization and ESG goals.
The challenge is that most systems were designed with limited flexibility. For decades, the industry has focused on making the conditioning of required outdoor air as efficient as possible through the use of high-efficiency equipment, tighter building envelopes and heat recovery technologies. While these investments are valuable, they still focus on the conditioning process itself, rather than re-examining the more fundamental question of how much outdoor air is actually necessary.
Limitations of the Standard Path
Commercial HVAC systems must comply with ASHRAE Standard 62.1: Ventilation for Acceptable Indoor Air Quality, which establishes minimum ventilation requirements to support acceptable IAQ. The standard provides several compliance pathways, but the Ventilation Rate Procedure (VRP) has long been the primary method utilized by engineers. VRP determines required outdoor airflow based on occupancy and floor area, making it straightforward to apply. However, that simplicity comes with tradeoffs that are increasingly difficult to ignore:
- The “Clean Air” Fallacy – VRP is built on the assumption that outdoor air is inherently clean, yet growing urban pollution, wildfire smoke and regional air quality differences are challenging that assumption more frequently than ever.
- Operational Waste – VRP delivers ventilation for peak occupancy rather than typical daily conditions, which translates to buildings often conditioning far more outdoor air than they actually need.
- System Oversizing – VRP’s prescriptive approach can lead to oversized mechanical systems, increasing capital costs, energy waste and embodied carbon.
Conditioning outdoor air means heating it in winter, cooling it in summer and managing humidity year-round. For buildings pursuing LEED, WELL or Fitwel certification, or net-zero performance targets, VRP compliance alone can consume a large share of the available energy budget.
A Performance-Based Alternative
ASHRAE 62.1 includes a second compliance path: the Indoor Air Quality Procedure (IAQP). While VRP prescribes fixed outdoor airflow rates, IAQP is performance-based, focused on controlling specific contaminants through filtration, air cleaning technologies and demand-based ventilation. Rather than assuming a set volume of outdoor air will achieve acceptable conditions, IAQP requires that IAQ performance be demonstrated and maintained. This approach can significantly reduce the amount of outdoor air that must be conditioned – often while improving IAQ – and introduces accountability by tying compliance to measured outcomes.
That accountability is well matched to where the broader IAQ conversation is heading. Tenants and their employees are placing greater scrutiny on IAQ, and sustainability certifications increasingly reward measurable IAQ outcomes. At the federal level, the recently reintroduced bipartisan Airborne Act proposes tax incentives for IAQ assessments and HVAC upgrades. It encourages the use of IAQP when it proves to be the more energy-efficient option, signaling a shift toward performance-based outcomes over prescriptive inputs.
Despite being a valid ASHRAE 62.1 compliance pathway, IAQP has seen relatively limited adoption. Its use requires identification of Contaminants of Concern, performance modeling and ongoing verification of acceptable IAQ – steps that can add complexity compared to the prescriptive nature of VRP. For many engineers, VRP has simply been easier to calculate, document and defend. That dynamic, however, is beginning to change.
Putting IAQP to Work
For new construction and major renovations, IAQP is a design-phase decision. Emerging modeling tools will soon allow engineers to compare VRP and IAQP side by side, quantifying energy impact, equipment sizing implications and projected cost savings before the design is finalized. When applied early, IAQP can right-size a system from the start, reducing both capital and operating costs.
While new construction offers a blank slate, existing buildings present a different set of constraints, but the opportunity is equally real. When occupancy levels increase beyond what a space was designed for, or space usage changes significantly, the original ventilation design may become obsolete. For example, when a low-density office space is converted to a high-density collaboration center, the original HVAC system may no longer be adequate to meet IAQ requirements under VRP. However, a full mechanical overhaul is rarely feasible or budget-friendly. This is where an Air Quality Management (AQM) strategy provides a bridge.
By integrating an AQM system directly into the existing building management system (BMS), facilities can transition to a more responsive approach to air quality. These systems provide a cost-effective solution that works in concert with existing HVAC infrastructure to continuously monitor specific contaminants and respond immediately to deviations from setpoints. When levels rise, the system activates integrated purification units in affected zones. When acceptable thresholds are restored, it shuts off. The result is targeted, verifiable IAQ performance without the cost or disruption of mechanical redesign.
The Opportunity
VRP has been the industry default because it’s familiar and defensible, not because it’s inherently better. Until recently IAQP lacked the tools needed to clearly quantify its benefits. However, as new modeling tools come online, IAQP is emerging as a practical, defensible strategy – one that can bring real value to commercial buildings, where an estimated 30% of energy used is wasted.
The question now isn’t whether better IAQ and lower energy use can coexist, it’s why we would continue designing buildings that treat them as a tradeoff.
Jason Jones is Director of Air Quality Management at Fellowes, where he works with engineers, facility professionals, building owners and HVAC distributors to implement air quality strategies for today’s commercial and institutional spaces. Learn more at www.fellowes.com/air.