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 patent pending 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.

Thermaduct InspiralR and Floval round and flat oval ductwork

InspiralR & Floval Preinsulated Spiral & Flat Oval


  • Patent Pending
  • UL 181 Listed
  • Kingspan KoolDuct Aluminum Interior
  • 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
  • Simple Connection System for Easy Installation
  • Lining options available for special applications
Lightweight Double Wall Spiral Ductwork InspiralR

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.


InspiralR and Floval fittings arrive pre-fabricated with included coupling and connection materials. Even with all this included, we still are able to offer significant weight savings when compared to traditional metal ductwork.

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

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.

preinsulated spiral ductwork
Pre-Insulated Spiral Ductwork System Indoor Commercial Industrial
Pre-Insulated Spiral Ductwork InspiralR
Thermaduct InspiralR factory spiral duct
Preinsulated double wall spiral duct system
preinsulated flat oval  ductwork
InspiralR Floval preinsulated ductwork

See Thermaduct's InspiralR in Action

Product Literature

Download the latest literature in PDF Format

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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