Round Rooftop Spiral Duct System

Thermaround Outdoor Ductwork System


Thermaround was introduced in 2019, designing the best parts of our Thermaduct system to have a more efficient shape for outdoor dynamic loads. As a non-metal alternative to spiral or round rooftop ductwork, Thermaround is a pre-insulated solution that offers your duct, insulation and cladding all in one product. Strong flanged connections allow this round solution to install fast and easy. Our patented process allows for a continuous cladded surface with as few as one solvent welded seam!

With a standard 1000 micron vinyl cladding cladding that offers the same weather resistant protection as rectangular Thermaduct, Thermaround is an excellent lightweight solution for the outdoor elements. This high R-value system offers an installed R-12 insulated value and extremely low air leakage. Thermaround offers multiple cladding options with both our vinyl or architectural metal for a durable solution that will naturally shed water. In the interior, air passes over a smooth aluminum phenolic surface free from loose fibers to give your building better IAQ performance.

Round Thermaduct Outdoor Ductwork


  • Patented Product
  • Installed R12 Insulated Value
  • 10" Positive, 8" Negative Pressure Class
  • UL 181 Listed InspiralR Interior
  • 1000 Micron UV Stable Vinyl Cladding
  • High Static Pressure Design
  • Lightweight Duct System
  • Gored Elbows - No Need for Turning Vanes
  • Low Air Leakage
  • Easy to Install, Fast Connections

Thermaround is an award winning product highlighted in:

Outdoor Duct Systems in Rectangular and Round

Factory Laminated & Virtually Seamless Vinyl Cladding

With a continuous cladded surface, Thermaround virtually eliminates common areas of water intrusion. Our 1000 micron, UV stable vinyl cladding is factory applied to our closed cell insulation with a full lamination process for a permanent bond. This strong barrier keeps outdoor elements out and conditioned air in to ensure high efficiency air distribution.

Duct sections are designed to have as few as one solvent welded seam for an uncompromising protective surface that requires no field installation of cladding.

Pre-Insulated Spiral Duct Systems – Thermaround

Outdoor Efficiency - Designed with Architects in Mind

Whether your application is looking for “cool roof” efficiency or just “cool” colors, Thermaround is now available with an optional Kynar finish metal exterior. This opens up more opportunities for architectural application where the look of your ductwork play a key role in building design, while still allowing for the pre-insulated quality of Thermaround.

Find out more about our Architectural Options

Near Zero Air Leakage

Energy Efficient Air Distribution Perfect for Exterior Applications

Preinsulated System

Thermaround provides an installed R12 insulated value without the need for additional duct insulation

Ease of Installation

With Thermaround's lightweight duct and fast connection system allow you to install more outdoor duct per day

10 Year Limited Warranty

Thermaround is backed by a 10 year limited warranty

Thermaduct and Thermaround Kingspan KoolDuct Fortified with 1000 micron vinyl Thermaduct

Pair Easily with Thermaduct Outdoor Rectangular Ductwork

Thermaduct and Thermaround both provide a factory laminated surface with a minimal areas of water intrusion. Applications that require both round and rectangular ductwork will find no better exterior ductwork solution than our outdoor products.

Both products install easily and provide near zero air leakage. Our patent pending Thermaround system requires installing contractors to apply sealant, connect sections together with an offset coupling and use a draw band connection for fast and easy installation.

Thermaduct and Thermaround truly are Outdoor Duct Solved!

See Thermaround In Action

2022 Thermaduct Round Installation Training - Connections |

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Thermaround Outdoor Pre-Insulated Phenolic Ductwork

Thermaround uses a smooth aluminum Kingspan KoolDuct interior for a high quality, fiber free insulation that is protected by our 1000 Micron vinyl cladding. Because of this, our round outdoor duct system is great for almost any application.

Hospitals and Healthcare Environments

Schools and Universities

Hotels and Multifamily Structures

Commercial and Industrial Applications

Pools and Natatoriums

Phenolic Duct Installation

See How Thermaduct Products Install in the Field

While our products will feel very familiar to traditional ductwork, we have a brief online training course to cover the differences that should be observed when installing an outdoor phenolic duct system.


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Thermaduct Product Information

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