US Patent 8667995 Insulated ducts and insulated ductworks

A duct for use in an HVAC system is provided. The duct including an outer tube. The duct also including an inner tube capable of conveying forced air. The inner tube extending within the outer tube and along the outer tube. The duct further including a plurality of support elements spanning between the outer tube and the inner tube. The elements extending along the inner tube and the outer tube. The elements defining a plurality of channels between the outer tube and the inner tube. The outer tube, the inner tube and the elements are unitary.