When building out an HVAC spiral pipe system, there are three main classifications to consider: Application of the system (commercial building, super market, residential home, etc.), air velocity (low – high), and pressure levels (low – high). Each of these classifications work together to create the ideal system in terms of efficiency, effectiveness, and safety for specific applications needs. Here are some tips on selecting the ideal velocity and pressure levels for your HVAC System.

How Pressure and Velocity Relate in Ductwork Systems

In most cases, velocity will impact the noise levels, friction levels, and vibration in the ductwork system, while pressure levels impact things like a ductwork’s strength, leakage, and deflection. To maintain proper airflow against friction in HVAC duct systems, it is most often necessary to match up the pressure of the system with the friction levels of its velocity. Therefore, it is common to see high velocity systems with high pressure levels, and low velocity systems with low pressure levels. Of course, there are benefits and drawbacks to using a high or low pressure/velocity system – depending on your unique application needs.

Pros and Cons of Low Pressure, Low Velocity Systems:




Low noise production

Larger ductwork – harder to install
Greater energy efficiency

Larger upfront cost

Lower friction levels

Not capable of particle conveyance


Pros and Cons of High-Pressure, High Velocity Systems:


Pros Cons
Smaller duct size for easier installation Less energy efficiency
Lower upfront costs Produce a good amount of noise
Faster to cool down large air spaces with no leakage Difficult to maintain zoned climate control


While you can use a either system in numerous residential and commercial applications, it is more common to see low pressure/low velocity systems used in small-to-mediums buildings that are sensitive to noise. Examples could include churches, hotels, and movie theatres – just to name a few. High pressure/high velocity systems are great solutions for any application that has limited ductwork space, and are often a recommended system upgrade when building a new construction, or replacing an outdated system. While some high velocity/pressure systems have built in sound-deadening technology, it is important to remember that these systems distribute air at very high velocities and concentrations –  making them generally louder and more intense systems.

Contact leading duct manufacturer, Spiral Mfg. at 763-755-7677 or info@spiralmfg.com for help designing, purchasing, and installing your next HVAC System.