Ductwork layout with building plans illustrating ASHRAE ventilation design.

Beyond Fresh Air: Why ASHRAE’s Ventilation Standards Need Active Air Cleaning

by Blog

The COVID-19 pandemic fundamentally changed how we think about indoor air quality. Suddenly, terms like “air changes per hour” and “MERV ratings” entered everyday conversations. But as we’ve learned more about airborne pathogen transmission, a critical question has emerged: Is bringing in fresh outdoor air enough to keep us safe? Recent research suggests the answer is more nuanced than we might expect. While ASHRAE ventilation standards provide essential foundations for healthy buildings, they may not be sufficient on their own for rapid pathogen control—especially when every minute counts for infection prevention. 

The Gold Standard: ASHRAE Ventilation Rate Procedure 

ASHRAE has long been the authority on indoor air quality standards. Their Standard 62.1, particularly the Ventilation Rate Procedure (VRP), serves as the backbone for ventilation design in buildings across North America. 

What Makes the VRP Valuable 

The VRP isn’t just about pumping in outdoor air—it’s a comprehensive system that addresses multiple aspects of indoor air quality: 

  • Tailored Ventilation Rates: Rather than a one-size-fits-all approach, the VRP prescribes specific outdoor air rates based on space type and occupancy. A computer lab has different requirements than a science laboratory or office space, reflecting the unique contamination sources and occupancy patterns of each environment. 
  • Holistic System Design: The standard goes far beyond ventilation rates, covering everything from building envelope design to prevent moisture problems, proper filter specifications (MERV-8 or higher), and strategic placement of outdoor air intakes to avoid contamination sources. 
  • Smart Air Management: Perhaps most importantly, the standard classifies indoor air into four categories based on contamination levels, with strict rules about where that air can be recirculated. This prevents contaminated air from spreading throughout a building. 
  • Continuous Evolution: ASHRAE standards are living documents, regularly updated based on the latest research and real-world performance data. 

The Fresh Air Limitation: New Research Reveals Critical Gaps 

While the VRP provides excellent general indoor air quality, recent research by ASHRAE members Brett Duffy and Dr. Margaret Scarlett has revealed a significant limitation when it comes to rapid pathogen control. 

Their study compared traditional ASHRAE ventilation methods against continuous active in-room air cleaning devices (CA-IRAC) using bacteriophage MS2—a surrogate for dangerous pathogens like SARS-CoV-2 and influenza viruses. 

The 4-Minute Problem 

The results were striking. In the critical first four minutes of exposure: 

  • Active air cleaning: 70% pathogen reduction 
  • ASHRAE 62.1 ventilation: Just 1.5% reduction 
  • Enhanced ventilation (Standards 170 & 241): 32-50% reduction 

Why does this matter? Because respiratory infections can occur within minutes of exposure to infectious particles. By the time traditional ventilation achieves significant pathogen reduction, exposure may have already occurred. 

Dilution vs. Elimination: A Fundamental Difference 

The research highlights a crucial distinction: outdoor air ventilation dilutes pathogens by mixing contaminated indoor air with clean outdoor air and exhausting the mixture. Active air cleaning devices eliminate pathogens by destroying them within the space. 

Think of it this way: dilution is like adding clean water to muddy water—you reduce the concentration, but the mud particles are still there. Elimination is like filtering out the mud entirely. 

The Path Forward: Complementary Strategies to ASHRAE Ventilation

This doesn’t mean we should abandon fresh air ventilation—quite the opposite. The research suggests that the most effective approach combines both strategies: 

Why We Still Need Fresh Air 

Outdoor air ventilation remains essential for: 

  • Removing carbon dioxide and body odors 
  • Controlling humidity levels 
  • Diluting chemical contaminants from building materials and furnishings 
  • Providing the psychological benefits of fresh air 
Where Active Air Cleaning Excels 

Continuous active air cleaning devices provide: 

  • Rapid pathogen reduction when it matters most 
  • Consistent performance regardless of outdoor air quality 
  • Energy efficiency compared to heated/cooled outdoor air 
  • Protection against both known and unknown airborne threats 

Practical Implications for Building Operators 

For facility managers and building operators, this research suggests several actionable steps: 

Immediate Actions: 
  • Assess current ventilation performance against ASHRAE standards 
  • Consider portable or installed active air cleaning devices for high-risk spaces 
  • Ensure existing ventilation systems are properly maintained and commissioned 
Long-term Planning: 
  • Design new systems with both adequate ventilation and active air cleaning 
  • Monitor emerging ASHRAE guidance on integrated approaches 
  • Consider spaces with high transmission risk (meeting rooms, cafeterias, classrooms) as priorities for enhanced air cleaning 

Looking Ahead: The Future of Indoor Air Quality 

The pandemic taught us that indoor air quality isn’t just about comfort—it’s about health and safety. As ASHRAE continues to evolve its standards based on emerging research, we can expect to see greater integration of active air cleaning technologies alongside traditional ventilation approaches. 

The goal isn’t to choose between fresh air and air cleaning—it’s to use both strategically. Fresh air provides the foundation for healthy indoor environments, while active air cleaning provides the rapid response needed for pathogen control. 

In our interconnected world, where people spend up to 90% of their time indoors, this dual approach may well become the new standard for truly safe and healthy buildings. 

 

This analysis is based on research by ASHRAE members Brett Duffy and Dr. Margaret Scarlett, published in peer-reviewed studies on ventilation effectiveness and pathogen control. Building operators should consult with qualified HVAC professionals when implementing changes to ventilation or air cleaning systems. 

Crowded indoor space with ASHRAE logo, representing efforts toward better indoor air quality.

Breathe Easy: ASHRAE’s Guidelines for Better Indoor Air

by Blog

Ever wonder what makes the air inside buildings healthy to breathe? ASHRAE publishes standards and guidelines for indoor air quality. Here’s what you need to know in plain language. 

What Are These Guidelines? 

Think of ASHRAE Standard 62.1-2022 as a rulebook for good indoor air in commercial facilities. It sets minimum requirements for ventilation (bringing fresh air in) and other measures to keep indoor air healthy for people. The goal is simple: make sure the air we breathe indoors won’t make us sick. 

Who Do These Guidelines Affect? 

These guidelines apply to most buildings where people spend time, except for residential homes. They’re used when: 

  • Building new structures 
  • Adding to existing buildings 
  • Making certain changes to buildings 
  • Improving air quality in older buildings 

Better Indoor Air: The Main Points Made Simple

Fresh Air Systems 

The guidelines explain how to design, install, and maintain systems that bring fresh air inside and clean the air that’s already there. 

Indoor Air Pollutants 

The rules address things that can make indoor air unhealthy, including: 

  • Outdoor pollution coming inside 
  • Dust and chemicals from construction 
  • Moisture and mold 
  • Cigarette smoke 

Outdoor Air Quality 

Before designing a ventilation system, builders need to check if the outdoor air in the area is clean enough. If it’s not, they must add filters or air cleaners to remove particles and harmful gases. 

Equipment Requirements 

The guidelines have specific rules for air system parts like: 

  • Where outdoor air enters the building (keeping these intakes away from exhaust fans, garbage areas, and other sources of pollution) 
  • Surfaces that the air flows over (making sure they resist mold) 
  • Drain pans (ensuring they don’t become breeding grounds for bacteria) 
  • Humidifiers (devices that add moisture to the air) 

There’s also emphasis on preventing Legionnaires’ disease, a serious type of pneumonia that can spread through water systems. 

Air Classification 

Not all indoor air is equal. The guidelines sort air into four classes based on how contaminated it might be and set rules for when this air can be reused or moved to other areas. 

Determining How Much Fresh Air Is Needed 

Designers can use several methods to figure this out: 

  • A straightforward approach based on room type and size 
  • A more complex method analyzing specific pollutants 
  • Guidelines for systems using natural airflow (like windows) 

Keeping It Clean 

The rules emphasize keeping air ducts clean during construction and making sure fresh air dampers (valves that control airflow) work properly before people move in. 

Ongoing Maintenance 

Regular upkeep of ventilation systems is required to ensure they continue working effectively. 

Checking Results 

For projects using the more complex design method, testing is required after completion to verify the air is actually clean. 

ASHRAE: Your Resource for Better Indoor Air 

These guidelines are constantly being updated as new research emerges. While following them isn’t legally required (unless local building codes say so), they’re widely recognized as the gold standard for healthy indoor air. By understanding these basics, you can better appreciate the behind-the-scenes work that goes into making the air in your workplace, school, or public buildings safe to breathe. To fully understand the standard, you can access a readable version of the entire document by visiting ASHRAE’s Technical Resources. 

 

AHR 2025 logo sign at the entrance of the Orlando conference, welcoming attendees from the HVAC industry.

CASPR Technologies at AHR 2025: Elevating Indoor Air Quality in the HVAC Industry

by Blog
AHR 2025 logo sign at the entrance of the Orlando conference, welcoming attendees from the HVAC industry.
ASHRAE logo displayed at AHR 2025 conference, highlighting the organization’s leadership in HVAC and indoor air quality standards.

The AHR 2025 conference in Orlando was an unparalleled experience for CASPR Technologies, bringing together industry leaders, innovators, and professionals from across the HVAC sector. The event served as the perfect platform for us to connect with experts, exchange ideas, and demonstrate how CASPR’s advanced technology is setting new standards for Indoor Air Quality (IAQ). Conversations throughout the event reaffirmed what we already knew—IAQ is no longer an afterthought. It has become a fundamental pillar of HVAC system design, implementation, and maintenance. As regulatory standards continue to evolve and awareness grows, HVAC professionals are seeking proven, data-driven solutions that ensure both safety and efficiency in every environment. Our team at CASPR Technologies was proud to be at the forefront of these discussions, driving innovation and education within the industry.  


The HVAC Industry is Bigger Than Ever 

AHR 2025 was a testament to the rapid growth and innovation happening within the HVAC industry. Walking the show floor, we were immersed in an environment that showcased the scale, diversity, and impact of the industry’s evolution. With thousands of exhibitors and attendees, it was clear that HVAC is a driving force behind healthier, more efficient indoor environments. The range of technologies on display—from cutting-edge filtration systems to AI-driven building automation—reinforced how IAQ is now woven into the very fabric of HVAC innovation. Whether in large-scale commercial applications, residential solutions, or specialized healthcare settings, there is an increasing demand for smarter, more effective air quality solutions. CASPR Technologies’ role in this landscape was undeniable, as we demonstrated how our continuous disinfection technology is revolutionizing the way air and surfaces are treated for safety and cleanliness. 


Indoor Air Quality Takes Center Stage 

One of the most notable shifts at AHR 2025 was the undeniable mainstream focus on IAQ. In past years, IAQ was often viewed as an added benefit—something to consider after primary HVAC functionalities were addressed. This year, however, it was front and center in every conversation. Whether discussing air purification, improved filtration, or next-generation pathogen treatment, professionals across the board recognized that effective IAQ solutions are essential for occupant health and safety. 

Moreover, we had the opportunity to engage with engineers, facility managers, and industry decision-makers who were all eager to learn how they could integrate validated, long-term IAQ solutions into their existing systems. Our team emphasized the importance of maintaining both air and surface cleanliness, as pathogen mitigation strategies must go beyond traditional approaches to create truly safe indoor environments. As regulatory bodies continue to set stricter standards for indoor air quality, it’s clear that data-backed, continuously active solutions like CASPR’s are becoming a necessity rather than an option. 

CASPR Technologies at AHR 2025 Takeaways: The Growing Importance of Pathogen Treatment 

At AHR 2025, pathogen treatment emerged as one of the most pressing topics in IAQ discussions, highlighting a growing industry-wide realization: true disinfection goes beyond air filtration—it must also address surface contamination. While traditional HVAC solutions have focused primarily on airborne pollutants, there is now an increasing demand for comprehensive, real-time mitigation strategies that tackle both airborne and surface-borne pathogens. 

As awareness grows around the role of pathogens in indoor environments, industry professionals are actively seeking proven solutions that don’t just capture contaminants but actively neutralize them. CASPR Technologies’ continuous disinfection technology captured the attention of engineers, facility managers, and HVAC specialists alike, who recognize that passive filtration alone is no longer enough. The ability to provide ongoing, automated pathogen reduction—without the use of chemicals or manual intervention—is becoming a critical requirement for modern IAQ strategies. 

Pathogen mitigation is no longer a reactive measure—it’s a proactive necessity. Schools, hospitals, commercial buildings, and residential spaces alike are prioritizing IAQ solutions that offer real-time, continuous protection against bacteria, viruses, and mold. Professionals expressed a strong desire for technologies that are not only validated by scientific data but also seamlessly integrate into existing HVAC systems without requiring costly modifications or downtime. 

The consensus was clear: effective, real-time pathogen mitigation is no longer just a competitive advantage—it’s an essential component of any serious IAQ strategy. As regulations tighten and industry standards evolve, there is a heightened expectation for continuous, scientifically backed solutions that can proactively reduce pathogens in the air and on surfaces. 

ASHRAE 241 and the Need for More Data 

A crucial industry discussion at AHR 2025 centered around ASHRAE 241, a new standard designed to provide guidelines for pathogen mitigation in indoor environments. While there is a growing push for IAQ advancements, one major challenge remains—the lack of published data for many existing technologies. Industry leaders stressed the importance of transparency in testing, safety validation, and efficacy reporting to ensure that businesses and consumers can make informed decisions about the technologies they implement. 

“I was surprised to find out how little people knew about IAQ standards and how a lot of the industry has no testing,” stated CASPR Representative Roberto Bonilla. 

CASPR Technologies has long been committed to setting the benchmark for industry standards. As part of our mission to deliver scientifically validated solutions, CASPR was the first technology to be tested for both safety and efficiency under ASHRAE 241 standards. This commitment to data-driven innovation positions CASPR Technologies as a trusted leader in the IAQ space, providing stakeholders with real, measurable results that demonstrate the true impact of our technology. 

CASPR Technologies at AHR 2025: A Packed Room and Engaging Conversations 

One of the highlights for CASPR Technologies at AHR 2025 was the overwhelming turnout for our paper presentation, ‘Assessing Indoor Air Quality in a Comparative Study Among ASHRAE Ventilation Standards Compared to a Control with a Continuous Active In-Room Air Cleaning Device.’  With over 120 industry professionals in attendance, the room was filled with engineers, facility managers, and HVAC experts eager to dive deeper into IAQ advancements. 

The level of engagement and thoughtful questions from attendees reinforced that IAQ is no longer an afterthought—it’s a critical priority for the industry. Throughout the presentation, we discussed the importance of data-driven decision-making in IAQ solutions and how continuous active air cleaning devices can complement ASHRAE ventilation standards. The discussions that followed were not only insightful but also highlighted the growing demand for validated, real-world data on the effectiveness of air purification technologies. 

Many professionals expressed keen interest in how CASPR’s continuous disinfection solutions could be integrated into their existing HVAC systems to enhance air quality and pathogen mitigation. The enthusiasm and dialogue that emerged from this session demonstrated the need for transparent testing, standardized guidelines, and proven results in IAQ technology—something CASPR is committed to delivering. 

AHR 2025 provided the perfect platform to engage with industry leaders and share groundbreaking research, and we’re excited to continue these conversations as we push the boundaries of IAQ innovation. 

Innovation at Every Level 

Innovation in HVAC isn’t just about upgrading large-scale systems—it’s about refining and enhancing every individual component to create a more efficient and effective IAQ strategy. From advanced sensors that monitor air quality in real time to next-generation filtration technologies that capture even the smallest particulates, the industry is experiencing a wave of breakthroughs designed to optimize air circulation, purification, and disinfection. Engineers and manufacturers are focusing on smarter, more adaptable solutions that integrate seamlessly into both new and existing HVAC infrastructures, making high-quality indoor air more accessible than ever before. These advancements are not just about compliance with evolving standards—they are about fundamentally reshaping how we think about air quality in homes, offices, hospitals, and public spaces. 

At CASPR Technologies, we are thrilled to be part of this movement, pioneering continuous disinfection technology that works in tandem with HVAC systems to ensure that indoor environments remain as safe and healthy as possible. Unlike traditional air treatment methods that rely on passive filtration alone, our technology actively neutralizes pathogens in the air and on surfaces, providing a comprehensive approach to IAQ improvement. Whether it’s for schools, healthcare facilities, commercial spaces, or residential buildings, our goal is to make clean, purified air the standard, not the exception. By pushing the boundaries of what’s possible in HVAC and IAQ innovation, CASPR Technologies is committed to shaping the future of indoor air quality—one breakthrough at a time. 

 

CASPR Technologies AHR 2025: A Successful Event with a Bright Future 

Reflecting on our experience at AHR 2025, one thing is clear—the future of IAQ has never been stronger. The sheer level of interest, engagement, and collaboration we witnessed at the event speaks to the growing demand for innovative air quality solutions. The industry is evolving rapidly, and businesses are prioritizing health-focused, sustainable technologies more than ever before. 

For CASPR Technologies, this event was more than just an opportunity to showcase our technology—it was a chance to be part of an industry-wide movement towards better, safer indoor environments. The connections we made, the conversations we had, and the enthusiasm we witnessed all point to an exciting future for IAQ innovation. 

To everyone who stopped by our booth, attended our presentation, and engaged with us in meaningful discussions—thank you. Your passion and curiosity inspire us to continue pushing the boundaries of what’s possible in IAQ and HVAC technology. We look forward to the future, knowing that together, we can redefine indoor air quality and make every indoor space a safer place to live and work.