International Energy Conservation Code (IECC)

Energy Efficiency

The IECC prescribes insulated siding as a building material that can be used as a form of continuous insulation outside of the building framing to provide the required total wall R-Value.

Insulated siding can be used to meet the R-Value/U-factor requirements of the IECC. The tested R-Value for insulated siding is required by the code N1101.10.1 (R303.1.1) to be labeled on the package of the insulated cladding.

IRC N1102.1.3 (R402.1.3) of the IECC allows the R-Value of insulated siding to be used as part of the prescriptive R-Value computation approach and may be used to satisfy the R-Value insulation requirements of Table R402.1.2 or R402.1.3.

When Table R402.1.3 is used for compliance, the R-value of the insulated vinyl siding must be reduced by .6 because there is already an R-value considered for the siding in this prescriptive approach. No reduction shall apply with other compliance methods when using insulated vinyl siding, such as the performance approach in (R402.1.4).