What R-value do I need for ductwork?
What R-value do I need for ductwork? R-value of 3.5 is required for buried ductwork and ducts installed in an unvented attic with roof insulation or in an unconditioned space (including both ventilated and unventilated crawlspaces). There are no R-value requirements for ductwork installed in an indirectly conditioned space. What is the minimum R-value for ductwork? “Supply and return air ducts and plenums shall be insulated with a minimum of R-6 insulation where located in unconditioned spaces and where located outside the building with a minimum of R-8 insulation in climate zones 1-4 and a minimum of R-12 insulation in...