InspiralR & Floval: Indoor Pre-Insulated Round and Flat Oval Solutions

Give your round and flat oval ductwork the increased performance with Thermaduct’s Inspiral R and Floval Duct Systems. These patented systems provide the increased air distribution efficiency of round or flat oval ductwork packaged in a light weight and high quality closed cell phenolic insulation. There’s no need to insulate separately as all ductwork reaches an R-6 insulated value.

Round Phenolic Pre-Insulated Ductwork

Thermaduct's InspiralR Round Phenolic System


  • Patented Systems
  • Easy to Install Flanged Connections
  • Kingspan KoolDuct Aluminum Interior
  • UL 181 Listed with Incredible Fire and Smoke Performance
  • Lightweight - Up to 70% Lighter than Metal
  • Passes the UL 181 Mold Growth Test
  • Pre-insulated R6 Ductwork
  • Low Air Leakage
  • Lining options available for special applications
Thermaduct indoor round ductwork

Compare InspiralR to Doublewall Metal Ductwork to See if Your Current Duct Might Be Weighing You Down

Lightweight and easy to install, InspiralR and Floval can drastically reduce the weight of installed spiral and flat oval by up to 75%. Because it is pre-insulated, there is no need to insulate separately.

With less weight hanging above heads, engineers and building owners can rest easy as their installation safety concerns can be addressed with InspiralR and Floval.

Pre-Insulated Double Wall Ductwork

Paintable Exterior Surface

For exposed applications, InspiralR and Floval have an exterior surface that can easily accept water based paints without the need of any special treatments. With the lower leakage rates, this can prevent dust accumulation from having streaks caused by air leaking out of traditional ductwork. The only difference you'll notice is with your utility bills!

Installing Pre-Insulated Round and Flat Oval

We designed our round and flat oval duct systems to be familiar to contractors. Time spent in the field comes at a cost and you will find that InspiralR and Floval connect easily.

Installing contractors will find it only takes about 3 minutes per connection for a virtually airtight seal.

See Thermaduct's InspiralR & Floval in Action

Near Zero Air Leakage

Energy Efficient Air Distribution

Pre-Insulated System

InspiralR and Floval will provide an R-6 Installed value

Ease of Installation

With less weight, you can install more duct per day.

10 Year Limited Warranty

Thermaduct's InspiralR and Floval are backed by a 10 year limited warranty

Lightweight Double Wall Spiral Ductwork InspiralR

Lightweight InspiralR Pre-Insulated Round Ductwork

Round Kingspan KoolDuct Phenolic Ductwork

InspiralR Round Phenolic Ductwork

Lightweight Ductwork System InspiralR

InspiralR Pre-Insulated Ductwork

InspiralR Pre-Insulated Duct System

Round Phenolic Ductwork

Thermaduct's InspiralR Phenolic

InspiralR Lightweight Spiral Ductwork

Round Kingspan KoolDuct

Lightweight Duct System

Round Phenolic Duct Systems

Thermaduct InspiralR Doublewall Alternative

InspiralR Round Duct System

InspiralR Round Duct System

Installing InspiralR Pre-Insulated Round Duct

Installing InspiralR Pre-Insulated Round Duct

Manufactured Phenolic Ductwork

InspiralR Pre-Insulated Double Wall Spiral Alternative

Flat Oval ductwork KoolDuct Interior

Flat Oval Insulated Duct

Flat Oval Phenolic Ductwork R-6

Pre-Insulated Flat Oval Double Wall Duct

preinsulated spiral ductwork

InspiralR Foodgrade Phenolic Spiral Ductwork

Pre-Insulated Spiral Ductwork System Indoor Commercial Industrial

InspiralR foodgrade pre-insulated spiral duct installation

Pre-Insulated Spiral Ductwork InspiralR

InspiralR Food Grade Double Wall Spiral Duct

Thermaduct InspiralR factory spiral duct

Manufactured Double Wall InspiralR Industrial System

Preinsulated double wall spiral duct system

InspiralR Preinsulated Spiral Industrial Ductwork

preinsulated flat oval  ductwork

Floval double wall flat oval ductwork

InspiralR Floval preinsulated ductwork

Thermaduct InspiralR Double Wall Spiral Ductwork

InspiralR and Floval Pre-Insulated Phenolic Ductwork

Both our round and flat oval systems use an aluminum Kingspan KoolDuct interior for a high quality, fiber free insulation. Because of this, InspiralR and Floval are great for almost any indoor application.

Hospitals and Healthcare Environments

Schools and Universities

Hotels and Multifamily Structures

Commercial and Industrial Applications

Pools and Natatoriums

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