Air Distribution: Shifting the Focus From Efficiency to Indoor Air Quality

Air Distribution Priorities After The Pandemic

COVID-19 caused a major shift in priorities across the globe. Priorities for air distribution are no different in that shift. Seemingly overnight, there was a renewed focus on health and safety over efficiency. The future of air distribution will continue to hold the well-being of occupants as the primary focus.

Reversing Air Distribution Priorities

AQC BlueDuct Underground Air Distribution ductwork duct
AQC’s BlueDuct Providing Displacement Ventilation From Beneath the Floor

Pre-COVID, engineers typically designed buildings to be optimized for energy efficiency. Indoor Air Quality (IAQ) was commonly an afterthought in designs, and only the minimum ASHRAE 62.1 standards were met. If you asked an engineer pre-pandemic how much time they spent on energy efficiency vs. IAQ, it likely heavily weighted toward energy efficiency.

Today, these priorities are reversed. IAQ is now the most crucial aspect of air distribution that engineers work to optimize. Once the pandemic began to impact everyday life, engineers put energy efficiency on the back-burner and began taking into account CDC and ASHRAE guidelines.

Some measures that have are now the utmost importance:

  • Increased minimum outside air setpoint
  • Continuous operation of the fan, even while the building is unoccupied (aka “purge”)
  • Installing higher efficiency filters with a larger pressure drop

Better IAQ Doesn’t Mean Inefficiency in Air Distribution

In general, the higher the IAQ, the lower the energy efficiency. There are exceptions to this generalization. One of these exceptions is air distribution and ductwork. Ductwork with a better seal equates to a smaller chance of water infiltration, which can cause mold and mildew. Additionally, better-sealed ductwork can cause less fan and compressor energy loss.  When reconsidering a building’s air distribution strategy, you can find additional solutions that maximize energy efficiency and indoor air quality.

Displacement Ventilation: Clean Air Entering the Room and Directing Air Up, to Avoid Mixing in the Occupied Zone

The Rise of Displacement Ventilation

Now the question is, how can buildings be designed differently to optimize for Indoor Air Quality? The answer is displacement ventilation. ‘Review of Ventilation Strategies to Reduce the Risk of Disease Transmission in High Occupancy Buildings,’ a study conducted by Tom Lipinski, Darem Ahmad, Nicolas Serey, and Hussam Jouhara, shows how effective displacement ventilation can be compared to traditional mixing ventilation in removing pollutants, including COVID-19 and influenza. Furthermore, there are many studies available that support these findings.

Displacement ventilation uses the natural buoyancy of warm air to stratify contaminated air out of the occupied zone. ASHRAE accepts displacement ventilation as a superior IAQ option by giving it a higher ventilation effectiveness value than traditional mixing ventilation systems. The challenge with displacement ventilation is distributing the air to the low wall and floor. Additionally, the floor does not have interstitial space below it, like the ceiling has above it. Innovative solutions able to duct air through the floor give engineers the ability to implement displacement ventilation in buildings they wouldn’t otherwise have the capability to use. Underground ductwork with AQC’s BlueDuct is one of those solutions.

Awareness for Ductwork IAQ in Existing Buildings

When the dust settles from the pandemic, IAQ will retain its important standing. COVID-19 has reaffirmed that buildings must be designed to promote occupant wellbeing, regardless of a pandemic. Additionally, many in the HVAC industry are now familiar with source removal technologies like UVGI, bipolar ionization, or simply higher efficiency filters. However, more important than source removal is source control.

AQC BlueDuct Air Distribution
AQC’s BlueDuct Pairs Improved IAQ with Energy Efficiency

For COVID-19, source control meant social distancing, masks, and hand sanitizer. Moving forward, HVAC system designers will implement more source control measures within buildings. One example of this is high-performance ductwork.

Duct systems in commercial buildings are notorious for hosting mold and mildew. Water that infiltrates the duct and insulation is conducive to the growth of mold and mildew. Furthermore, substituting cheap ductwork with high-performance ductwork to prevent the growth and harboring of mold and mildew is critical for IAQ.

More Energy Consumption, More Opportunity to Save

CDC and ASHRAE recommendations are going to require more energy. Increasing air changes per hour and minimum outside air damper position result in increased energy consumption. Also, this increase in consumption will result in higher energy bills. Post-pandemic, building managers will be required to double down on energy efficiency to prevent utility bills from skyrocketing. Additionally, duct leakage is the largest cause of energy loss in an HVAC system. Taking a proactive approach to duct leakage by installing a high-performance air distribution system that addresses IAQ and energy efficiency removes this inefficiency.

The Future of Air Distribution

Post-pandemic buildings will be different. IAQ will impact the design and operation of HVAC systems. Building energy consumption will be a secondary effect of maintaining healthy buildings. Furthermore, designers now have the tools to benefit from better IAQ and energy efficiency. Going forward, air distribution will take on a bigger responsibility in maintaining high IAQ and energy efficiency standards. Now, designers need to begin rethinking air distribution options, like displacement ventilation, with underground air distribution or high-performance ductwork that minimizes mold and mildew.

Air distribution BlueDuct
Custom-Built BlueDuct System to Fit Around a 100ft Curved Concrete Wall

BlueDuct: The Commercial Air Distribution Solution

AQC’s BlueDuct is one excellent option that provides superior IAQ and outstanding energy efficiency. BlueDuct is customizable for nearly any application.  Creative flexibility is a benefit of BlueDuct that is not available with other options on the market. Since 2001, the innovative underground duct solution has provided cutting-edge IAQ and energy efficiency that far surpasses current standards. Furthermore, the levels provided can future-proof your system from the changing standards.

About AQC

AQC Industries’ owners and managers are leaders in the residential, commercial, and industrial HVAC industry. The company’s mission is to transform an often overlooked but critical solution for the HVAC industry: underground duct systems. Moreover, AQC engineers, technicians, and representatives work closely with customers to provide high-quality, consistent CAD services and training. Finally, its underground, outdoor, and indoor duct systems are available through a network of distributors and representatives across North America.


Click here or contact the team at AQC to learn more about how BlueDuct can increase your facility’s IAQ and energy efficiency at the same time.

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