Traditional duct systems often rely on external insulation applied in the field. With space issues, environmental factors and inconsistent application of protective barriers, this can introduce potential performance gaps that lead to thermal losses, especially in the outdoor rooftop applications or inside the building in unconditioned spaces like attics or mechanical rooms.

Pre-insulated phenolic ductwork is built from high-performance insulation—often up to R-12 or greater—with phenolic consistency built into the duct system itself. By delivering uniform thermal protection and preventing the leakage of conditioned air, phenolic systems offer a more efficient solution for applications that require insulated ductwork. The result: less heat gain or loss, and a system that works more efficiently year-round.

Air leakage is a major cause of HVAC inefficiency. Poorly sealed duct joints and seams can reduce system performance by as much as 20%, according to Department of Energy research. Thermaduct’s pre-insulated duct systems are factory-sealed, ensuring ultra-low leakage rates that exceed SMACNA Class 3 or better.

While there are field connections on any duct system, Thermaduct makes it easy to for contractors to install with simple and familiar connections and online training available 24 hours a day. All of our systems easily can reach extremely low leakage rates.

Field-installed ductwork can be prone to mistakes—misapplied insulation, improperly sealed joints, or variable workmanship across installers. These issues contribute directly to system inefficiency and energy waste.

With prefabricated insulated ductwork, much of the labor and variability is removed from the job site. Thermaduct’s systems arrive ready to install with all of the insulation, vapor barriers, and precise dimensions already figured out — reducing labor time, minimizing waste, and ensuring performance consistency across your entire duct system.

When duct systems leak air or lose heat, HVAC units must work harder to maintain indoor temperatures. This leads to increased runtime, premature wear, and higher repair or replacement costs over time.

By maintaining better thermal integrity and preventing leakage, insulated ductwork helps HVAC systems operate within optimal parameters, reducing load and extending equipment life. Greater duct efficiency that can lower load requirements also open the door for downsized systems, saving on both shorter term purchase costs and long term operating expenses.

Modern energy codes require strict insulation and leakage standards for duct systems. Pre-insulated ductwork makes compliance easier by exceeding insulation R-value and air leakage requirements from the outset. With a more consistent

Additionally for projects seeking LEED certification or other sustainability designations, Thermaduct’s products can contribute valuable points through improved energy efficiency and indoor air quality. This positions your building for long-term environmental and economic benefits.