ARC 0412D

ARC 0412D

INSPECTIONS AND APPEALS DEPARTMENT[481]

Adopted and Filed

Rulemaking related to state building code

    The Department of Inspections, Appeals, and Licensing hereby amends Chapter 301, “State Building Code,” Iowa Administrative Code.

Legal Authority for Rulemaking

    This rulemaking is adopted under the authority provided in Iowa Code sections 103A.7 and 103A.8A.

State or Federal Law Implemented

    This rulemaking implements, in whole or in part, Iowa Code chapter 103A.

Purpose and Summary

    Iowa Code section 103A.7(1) provides that the State Building Code Commissioner is empowered and directed to formulate, adopt, and amend or revise State Building Code rules. Pursuant to Iowa Code section 103A.7(2), the rules shall include (among other things) reasonable provisions for the conservation of energy through thermal efficiency standards for buildings intended for human occupancy and that are heated or cooled and lighting efficiency standards for buildings intended for human occupancy that are lighted. Additionally, pursuant to Iowa Code section 103A.8A, the State Building Code Commissioner shall adopt as a part of the State Building Code a requirement that new single-family or two-family residential construction shall comply with energy conservation requirements.

    The purpose of this rulemaking is to amend the energy conservation provisions of the State Building Code to increase the acceptable air leakage rate when simulated energy performance analysis is utilized. For a number of years, the energy conservation rules of the State Building Code have amended the adopted International Energy Conservation Code (2012 Edition) (IECC (2012)) to increase the acceptable air leakage rate when using physical testing with a blower door from three air changes per hour to four air changes per hour (in Climate Zones 3 through 8, which encompass Iowa). This amendment can currently be found in subrule 301.24(9). Note that the physical testing of air leakage rate with a blower door is a mandatory provision that must be performed on all constructed residences.

    To demonstrate compliance, the IECC (2012) provides a general prescriptive route and an alternative performance route, or “simulated performance alternative.” As the name suggests, this alternative is a simulated analysis using software that is conducted on proposed residential construction (i.e., before construction is completed). The simulated energy performance analysis has many fields or building components, of which air exchange rate is just one. The acceptable air leakage rate under the IECC (2012) simulated energy performance analysis is three air changes per hour, and it is not currently amended by State rules. It has come to the Department’s attention that this has created confusion within the home builder industry and with local enforcement of these provisions, with some in the field believing that the amendment to acceptable air leakage rate for physical testing also applies to the acceptable air leakage rate that is one component of the simulated energy performance analysis. To alleviate this confusion, the Department is amending IECC (2012) by State rule to allow for four air changes per hour during the simulated energy performance analysis.

    Additionally, this rulemaking would make the simulated energy performance analysis less restrictive, consistent with the directives of Executive Order 10 (January 10, 2023). The Department has received preclearance for this rulemaking from the Administrative Rules Coordinator pursuant to Section IV(A)(i) of Executive Order 10.

Public Comment and Changes to Rulemaking

    Notice of Intended Action for this rulemaking was published in the Iowa Administrative Bulletin on March 18, 2026, as ARC 0123D. Public hearings were held on the following date(s):

     ?   April 7, 2026

     ?   April 8, 2026

    No one attended the public hearings.

    The Department received written comments from the Iowa Chapter of the American Institute of Architects, with comments related to the distinction between modeling and tested results, the appropriate response to the above-noted confusion in the industry, concerns regarding potential energy performance reduction, and more. The Department fully considered these comments; however, there were no changes made based upon them.

    No changes from the Notice have been made.

Adoption of Rulemaking

    This rulemaking was adopted by the Commissioner on June 16, 2026. Pursuant to Iowa Code sections 103A.7(1) and 103A.14, the State Building Code Advisory Council approved adoption of this rulemaking at a June 3, 2026, public meeting.

Fiscal Impact

     This rulemaking has no fiscal impact to the State of Iowa.

Jobs Impact

    After analysis and review of this rulemaking, no impact on jobs has been found.

Waivers

    Any person who believes that the application of the discretionary provisions of this rulemaking would result in hardship or injustice to that person may petition the Department for a waiver of the discretionary provisions, if any, pursuant to 7—Chapter 2504.

Review by Administrative Rules Review Committee

    The Administrative Rules Review Committee, a bipartisan legislative committee which oversees rulemaking by executive branch agencies, may, on its own motion or on written request by any individual or group, review this rulemaking at its regular monthly meeting or at a special meeting. The Committee’s meetings are open to the public, and interested persons may be heard as provided in Iowa Code section 17A.8(6).

Effective Date

    This rulemaking will become effective on August 12, 2026.

    The following rulemaking action is adopted:

    ITEM 1.  Adopt the following new subrule  301.24(12):

    301.24(12) Delete the first clause of the Standard Reference Design for Building Component “Air exchange rate” in Table R405.5.2(1) and insert in lieu thereof the following new clause: “Air leakage of 5 air changes per hour in Climate Zones 1 and 2, and 4 air changes per hour in Climate Zones 3 through 8 at a pressure of 0.2 inches w.g. (50 Pa).”

[Filed 6/16/26, effective 8/12/26]

[Published 7/8/26]

EDITOR’S NOTE: For replacement pages for IAC, see IAC Supplement 7/8/26.