Duct Insulation R-values: IECC/2006 vs. IECC/2009

In the International Energy Conservation Code (IECC)/2006, ducts or portions thereof that are located outside the building thermal envelope (BTE) are required to be insulated as per Section 403.2.1 of the 2006 International Energy Conservation Code (IECC), which requires that supply and return ducts be insulated to a minimum of R-8 and ducts in floor trusses be insulated to a minimum of R-6.

With the 2009 IECC on the horizon for adoption, I thought I would bring to your attention that Section 403.2.1 has been rewritten. Once the IECC/2009 is adopted, supply ducts outside the BTE in attics will be required to be insulated to a minimum of R-8 and all other ducts outside the BTE will be required to be insulated to a minimum of R-6.

As you can see, this is a significant difference between the 2006 and the 2009 editions of the IECC and it will be very important for mechanical plans to be labeled specifically for supply and return ducts.

Following the adoption of the 2009 IECC, if there are no supply ducts in the attic, all ducts outside the BTE will be required to be insulated with at least R-6 insulation.

If you have any questions of this matter, please contact me at.

Contact

Rob Austin
Code Assistance Unit
(609) 984-7609

Source:
Construction Code Communicator,Volume 22, Number 1, Spring 2010 (208k PDF)

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