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ZEN Industries eNewsletter:
February 2022

Duct Liner vs Duct Wrap

Both duct liner and duct wrap serve similar purposes. They are meant to insulate HVAC ductwork, preventing air leakage and condensation. Both are common methods of insulating duct, and in many applications either one can perform effectively.

But let’s take a closer look.

Duct WrappingDuct Wrap

  • Prevents air leakage, condensation, and energy loss
  • Can be retrofitted onto existing duct systems
  • More expensive (including labor) than duct liner

Duct Liner

  • Prevents air leakage, condensation, and energy loss
  • Available in specific NRC values for acoustical performance
  • Installed into the duct during fabrication, saving you field labor time
  • Optional Double wall systems for high negative pressure applications

When it comes to the basic function of insulating duct, both duct wrap and liner function well. Choosing the correct one for a specific job is about understanding the needs of your project. If the mission is to retrofit a warehouse, where a substantial portion of old duct will be left in place, then the only approach is duct wrap.

Duct InstallationFor commercial buildings where occupants engage in professional jobs and interact with the public and co-workers, the answer is duct liner. The main reason is acoustical performance.

The elastomeric foam or fibrous glass liner used to insulate the interior of ductwork offers acoustical insulation and vibration dampening properties.

Duct liner is often sold with specific Noise Reduction Coefficient (NRC) values. For a given design, the thicker the insulation, the higher the NRC value.

Duct Liner Density

Once the choice has been made to go with duct liner, the subject of liner density is often the next concern. For a specific job, how will the weight and thickness of duct liner impact the performance for a given job. Is thicker better?

The answer is not as easy as it once was. Today, advancements in materials technology make density alone less important to thermal and acoustical performance. In the mid-1980s, the performance-based ASTM C1071 duct liner standard was established for fibrous glass duct lining insulation. Instead of relying on density, this standard relies on thermal and acoustical properties of interior duct liner material.

Where density still must be considered is during installation and hanging. Density is directly related to weight, such that the denser the lining material, the more stress it will place on the duct supports, especially over the lifetime of the project.

Double Wall Insulation

Double wall lined duct takes the idea of duct insulation to its highest level, achieving several key qualities that are in demand by the HVAC industry today.

  • Double wall lined duct delivers the highest energy efficiency and tightest air seal
  • Reduces noise from airflow, fans, and connectors, and vibrations
  • Installation efficiencies, saving time often taken up by the application of external insulation.

The sheet metal interior wall protects the insulation from airflow while it stops fiberglass erosion. This keeps particulate build up from happening inside the ductwork which can give mold spores and microbes in the airflow a chance to take hold.

Built In for Affordable, Cutting Edge Performance

Duct wrapping must take place on the job site and requires an unknown quantity of labor. It may or may not be done well, depending on the experience of the labor and the configuration of duct supports on site.

Liner built into the duct adds cost to the fabrication process, but is entirely predictable, completely consistent in quality, and adds no time to the installation process. Therefore, when calculating the probable cost of wrapping duct with insulation, the additional cost of lined duct often balances out, ultimately delivering a better result for the same cost.

Interested in learning more about ZEN Industries and our capabilities in HVAC duct fabrication?.  Give us a call at 877-600-0274, or visit our Contact Us page today.

Partner with ZEN to Do More and Earn More

Let ZEN Industries be your partner in the HVAC Industry as an experienced, high-quality manufacturer of HVAC duct of all types. Our goal is to partner with our customers in ways that make the entire workflow from order to installation a seamless exercise in time and cost savings.

As an experienced fabricator of HVAC duct for over 22 years, ZEN Industries supplies traditional Rectangular Ductwork as well as Spiral Ductwork, Double Wall Spiral, , PCD Ductwork, and Industrial Welded Ductwork.


Success is All About Great Service

Founded in 1999 on a set of unbreakable core principles, ZEN strives to provide top-quality fabrication, advice, and planning for our customers.

The quality of our HVAC duct work is of the highest caliber and our price is competitive with the best in the industry. Of course, ZEN Industries Inc. gains its edge with unbeatable service, and service means people - it's about our experienced personnel and the relationships we build with each and every customer.

At ZEN Industries, we believe success is all about great service. Our affordable HVAC shop drawings, estimating services, and duct fabrication can be reached at 877-600-0274, or visit our Contact Us page today!

Learn more at www.ZENindustries.com

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