Double wall spiral ducts are, as the name suggests, comprised of two walls. First, there is the larger external duct that’s visible to everyone. Then , there’s the second inner spiral duct. These two components help ensure a more consistent airflow temperature during delivery. Double Wall (also called Dual Wall) insulated spiral pipe offers exceptional thermal and noise control, and it is the most reliable, durable, and permanent method of insulating spiral pipe.
The double wall spiral duct normally comes with fiber glass insulation.