Duct Insulation R Value Requirements

The following information applies to combined heating and cooling ducts in zone 4 areas.

Duct insulation r value requirements.

You can follow him on twitter at energyvanguard. Existing 3 4 inches of insulation. Or component performance alternative of section c402 1 5 roof solar reflectance and thermal emittance fenestration in building envelope. R value of r 6 is required for exterior ductwork or ducts installed in a ventilated attic or an unvented attic above a.

For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed your attic to reach r 30 if you live in zones 2 or 3. If the lesser r value most likely the duct r value is chosen the envelope of the building must be shown to comply with a performance based option. R value based method of section c402 1 3 u c and f factor based method of section c402 1 4. Insulation r value to match the supply duct.

And that means it s time to deal with duct insulation in a more meaningful way than just increasing the required r value to 8 for ducts in attics. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. Insulation r value must meet either the requirement for above grade walls or for exterior ducts. Recommended insulation levels for retrofitting existing wood framed buildings.

R value of 3 5 is required for buried ductwork and ducts installed in an unvented attic. Ashrae 90 1 also has a requirement of r 1 9 for supply ducts installed in indirectly conditioned spaces which includes plenum spaces above ceilings. Ashrae 90 1and the ieccboth require r 6 insulation for ducts in unconditioned spaces and r 8 or r 12 depending on the climate zone for ducts installed outside the building. Specific insulation requirements of section c402 2 thermal requirements of either.

The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process.