Arizona Has No Statewide Energy Code: What Phoenix, Tucson, and Your County Actually Require

1. What the Code Is and Who Enforces It

Arizona doesn't have a single mandatory residential energy code, and it isn't shy about saying so. The U.S. Department of Energy's own state profile for Arizona lists Current State Code - for both Commercial and Residential construction - as simply "None Statewide," with no effective date, adoption date, or state amendments given at all.¹ That's a structurally different starting point from most states covered on this site, and it means the honest answer to "what code does Arizona use" is "it depends entirely on which city, town, or county is issuing your permit."

What home rule means here

In Arizona, cities, towns, and counties adopt and enforce their own building and energy codes independently, with no state agency reviewing residential plans or setting a floor edition the way some home-rule states do. That means the code edition, the local amendments layered on top of it, and even whether an energy code applies at all can differ from one jurisdiction to the next - sometimes sharply, even between neighboring communities in the same metro area.

Who enforces it

Enforcement is entirely local: your city or town's building department reviews the permit for incorporated areas, and the county's planning and development department reviews permits for unincorporated land. There is no statewide plan-review desk and no statewide energy-code appeal process - each jurisdiction runs its own.

Climate zones

Arizona spans four IECC climate zones - 2B, 3B, 4B, and 5B - predominantly hot-dry and mixed-dry conditions, with the low desert around Phoenix and Yuma at the warmer end and the higher-elevation areas around Flagstaff at the cooler end.² Because there's no statewide code, these zone numbers only matter within whichever jurisdiction's adopted energy code actually references them - confirm your project's zone assignment with the specific city or county issuing your permit.

2. Where Jurisdictions Differ - Phoenix, Tucson, and Maricopa County

With no statewide baseline to compare against, the only meaningful answer is jurisdiction by jurisdiction. Verified directly against each jurisdiction's own published code-adoption materials:

The headline finding: even these three jurisdictions span three different postures on the same underlying question. Phoenix has already been enforcing a 2024-cycle energy code for over a year. Tucson is mid-transition, with a hard cutover date of July 1, 2026, and a clear rule about which permits fall on which side of it. And unincorporated Maricopa County - land outside any city or town's limits - has adopted the 2018 IECC but explicitly marked it voluntary in its own adoption record, while treating the accompanying 2018 IBC, IRC, IPC, IMC, and IFGC as mandatory.⁵ That's not a typo or an oversight - it's a jurisdiction deliberately choosing not to make its own adopted energy code mandatory, which is about as clear an illustration of "home rule" as exists anywhere on this site's state pages.

REScheck applicability follows the same pattern

DOE's own list of "States That Can Use REScheck to Show Compliance" includes Arizona with an asterisk, meaning REScheck use is by county or jurisdiction rather than statewide.⁶ In practice, that means REScheck is workable wherever a jurisdiction has both adopted a REScheck-supported IECC edition and actually enforces it as mandatory - Phoenix's and (from July 2026) Tucson's 2024 IECC editions both qualify on the first count. Unincorporated Maricopa County is a harder case: since its own energy code is voluntary, a compliance document tied to a code the county doesn't require may not be something its plan reviewers are even looking for. Confirm with the specific office issuing your permit before assuming a REScheck report is the right document.

3. Your Ways to Comply

Wherever a jurisdiction has adopted an IECC edition as mandatory - Phoenix today, Tucson from July 1, 2026 - the same general compliance paths apply, consistent with how the IECC's residential chapter is structured nationally:

Which path fits which project, where an IECC edition applies:

• Simple, code-minimum spec homes with standard framing - the prescriptive path is fastest through plan review and the cheapest to document.
• 2x4 walls, large window packages, or one weak component - the UA trade-off (REScheck) is usually the cheapest fix, where your jurisdiction's adopted edition is one REScheck supports and where that jurisdiction actually enforces its energy code as mandatory.
• Custom homes or designs the prescriptive/UA path can't cleanly capture - simulated performance costs more and takes longer, but it's the only path flexible enough for genuinely non-standard designs.
• Already paying for a HERS rating for a utility rebate or tax credit - use the ERI path and let that rating do double duty as code compliance where applicable.

Where REScheck fits in Arizona specifically. Phoenix's and Tucson's 2024 IECC-based codes both fall inside REScheck's supported 2009-2024 edition range.⁷ But "the tool supports the edition" and "your specific jurisdiction requires and accepts a REScheck printout" are two different questions in a home-rule state - and unincorporated Maricopa County's voluntary IECC adoption means a REScheck report may not be something its reviewers ask for at all. Tell us your jurisdiction before we run anything, so we confirm applicability rather than assume it.

What about Manual J? Wherever a jurisdiction has adopted an IRC edition - Phoenix's current 2024 IRC and Tucson's incoming 2024 IRC both do - Section M1401.3 requires heating and cooling equipment to be sized per ACCA Manual S based on loads calculated per ACCA Manual J or another approved equivalent method.⁸ That requirement is baked into the residential code itself, independent of whichever energy-code posture a jurisdiction has taken on REScheck. Because Arizona's code landscape is this fragmented, Manual J is the more universally useful order here: proper equipment sizing is good engineering regardless of which city or county is reviewing the permit, and it's the one report we can confidently say applies everywhere in the state.

4. Arizona-Specific Wrinkles

"Arizona code" isn't one thing - confirm the jurisdiction, not the state. With no statewide default and dozens of independent cities, towns, and counties, the single biggest risk on an Arizona project is assuming a code edition based on a neighboring city or a prior job. A builder working Phoenix and unincorporated Maricopa County jobs back to back is working under genuinely different regimes - one with a mandatory 2024-cycle energy code, the other with a voluntary 2018-cycle one - even though both sites might sit only a few miles apart.

Voluntary versus mandatory, inside the same adoption action. Unincorporated Maricopa County's own adoption record is unusually explicit about this: the same Board of Supervisors action that made the 2018 IBC, IRC, IPC, IMC, and IFGC mandatory listed the 2018 IECC and the 2018 International Green Construction Code as "(voluntary)" right alongside them.⁵ That's not a case of the county having "no energy code" - it has one on the books - it's a case of the county choosing not to enforce it as a permit condition. Don't assume "adopted" means "mandatory" anywhere in Arizona without checking how the specific jurisdiction worded its own adoption.

Permit-date cutovers matter and aren't uniform. Phoenix's 2024 code package took effect on a fixed date (August 1, 2025) tied to when the ordinance became effective. Tucson's transition is explicitly tied to submittal date: applications received on or after July 1, 2026 must comply with the 2024 International Codes, while applications received before that date continue under whatever edition was in effect at the time of submittal.⁴ A project that started design under one city's older code and is now applying for permit close to a cutover date needs to confirm which edition its actual application date falls under - don't assume based on when design work began.

Regional and joint review arrangements exist. Tucson and Pima County coordinate residential code review through the same local process, and Tucson's own Building Codes page frames adoption as a joint local review between the city and county before taking effect.⁴ That's a different arrangement than Phoenix, which adopts and amends independently of Maricopa County - two neighboring jurisdictions, two different governance models for how codes get updated.

Hot-dry and mixed-dry climate context. Most of Arizona's populated areas fall in Zones 2B and 3B - genuinely hot, dry summer design conditions that put more pressure on cooling-season provisions (duct location and insulation, high solar-gain glazing, air infiltration in a dry climate) than on the winter heating side most other states' energy codes emphasize. Whatever code edition your jurisdiction enforces, expect its climate-zone-specific tables to reflect that cooling-dominant reality.

What to ask your local building department before you finalize a compliance strategy:

1. Does this specific jurisdiction have a mandatory energy code at all, or is any adopted IECC edition voluntary here?
2. Which IECC and IRC editions does this jurisdiction currently enforce for residential permits, and is my project inside city limits, in unincorporated county land, or in a jointly-reviewed area?
3. Which code edition applies to my project: the one in effect at permit application, or at a fixed ordinance cutover date?
4. Do you require a Manual J load calculation to be submitted with the permit, or only upon request?
5. If a REScheck report is accepted here, which specific IECC edition and any local amendments should it be run against?

5. Frequently Asked Questions

Does Arizona have one statewide residential energy code? No. DOE's own state profile lists Arizona's Current State Code as "None Statewide" for both commercial and residential construction.¹ Each city, town, and county adopts and enforces its own code independently, with no state-mandated minimum edition.

Will a REScheck report be accepted for an Arizona permit? It depends on your specific jurisdiction. DOE marks Arizona's REScheck use as "Applicable by County or Jurisdiction" rather than a flat statewide Yes.⁶ Phoenix and (from July 2026) Tucson both enforce 2024 IECC-based codes REScheck supports; unincorporated Maricopa County's own IECC adoption is voluntary, so confirm with the specific office before assuming a REScheck report is what's needed.

Is a Manual J load calculation required in Arizona? Wherever a jurisdiction has adopted an IRC edition - Phoenix's and Tucson's current 2024 IRC editions both do - Section M1401.3 requires equipment sizing per ACCA Manual S based on ACCA Manual J loads.⁸ Because Arizona's adoption picture is this fragmented, we offer Manual J everywhere in the state regardless of a given jurisdiction's specific code posture.

Who prepares these reports? Travis Smith, The Plans Examiner. He holds the same certification your building department's plan reviewer holds; the specifics are at the end of this page.

My city or county isn't one of the ones covered on this page - what do I do? Arizona has dozens of cities, towns, and counties, each free to adopt its own code on its own timeline, so this page can't cover every jurisdiction by name. Check your building department's adopted-codes page or call the plan review desk. Tell us the jurisdiction when you order a report and we'll confirm the edition, and whether an energy code even applies as mandatory, before we run anything.

6. Get It Right the First Time - Before Plan Review Sends It Back

Need a Manual J load calculation? Because Arizona has no statewide default and IRC M1401.3's equipment-sizing requirement is the one thing that shows up consistently wherever a jurisdiction has adopted an IRC edition, a room-by-room Manual J is the most reliably useful report for an Arizona project. A Manual J report is $249 for homes up to 3,000 sq ft, $349 for 3,001 to 4,500 sq ft, and $449 for 4,501 to 6,000 sq ft. Larger homes or projects with three or more systems are quoted from your plans.

Need a REScheck report too? Tell us the city, town, or county where you're pulling the permit and we'll confirm whether that jurisdiction requires and accepts REScheck, and which IECC edition to run it against, before charging you anything. A REScheck report is $149 once we've confirmed your jurisdiction accepts it.

Need both? The combined Manual J + REScheck package is $349 for homes up to 3,000 sq ft - one submission covering the equipment-sizing requirement under the residential code and the envelope compliance requirement, where an energy code applies as mandatory in your jurisdiction.

Every report comes with the same guarantee: accepted by your building department, or we revise it free until it clears.

Contact us with your plans and the city, town, or county where you're pulling the permit, and we'll confirm the adopted code edition - and whether it's even mandatory there - before you pay for anything.

Verification Appendix

Every jurisdiction-specific claim on this page was checked directly against that jurisdiction's own published code-adoption page or ordinance document during this research pass - not a national aggregator or a secondary blog summary, except where explicitly noted below.

1. Arizona = "None Statewide" for both commercial and residential; "Can use COM/REScheck" = "Applicable by County or Jurisdiction" for both. VERIFIED (primary source). energycodes.gov/status/states/arizona's own State Profile table states this directly.¹

2. Arizona appears with an asterisk on DOE's own list of states that can use REScheck, denoting county/jurisdiction-level applicability rather than statewide. VERIFIED (primary source). energycodes.gov/states-can-use-rescheck-show-compliance lists "Arizona*" directly, with the asterisk defined on the same page as denoting county-or-jurisdiction-level use.⁶

3. Phoenix = 2024 IECC, effective August 1, 2025 (Ordinance G-7397). VERIFIED (primary source). The City of Phoenix's own 2024 IECC amendment change-proposal PDF states directly: "Adopted by City of Phoenix Ordinance G-7397 effective August 1, 2025," following City Council approval June 18, 2025. Corroborated by up.codes' own Phoenix Energy Code 2024 adoption page, which lists the same effective date.³

4. Tucson = 2024 International Codes (including IECC), effective July 1, 2026 for new submittals; earlier submittals reviewed under prior editions in effect at time of submittal. VERIFIED (primary source), re-fetched directly for this page. The City of Tucson's own "Building Codes" page states this in its own words: "All permit applications and related submittals received on or after July 1, 2026, must comply with the 2024 International Codes and amendments as adopted by the City of Tucson and in effect as of that date... Applications and related submittals received before July 1, 2026, will continue to be reviewed under the code editions in effect at the time of submittal, unless approved by the Building Official."⁴

5. Unincorporated Maricopa County = 2018 IECC and 2018 IgCC adopted as voluntary, alongside mandatory 2018 IBC/IRC/IPC/IMC/IFGC and 2017 NEC, approved by the Board of Supervisors August 17, 2022. VERIFIED (primary source), re-fetched directly for this page. Maricopa County's own "Adopted Regulations" index states directly: "Text Amendment to the Maricopa County Local Additions & Addenda to adopt and amend the following construction safety codes: 2018 International Building Code, 2018 International Residential Code, 2018 International Plumbing Code, 2018 International Mechanical Code, 2018 International Fuel Gas Code, 2018 International Green Code (voluntary), 2018 International Energy Conservation Code (voluntary), 2018 International Existing Building Code, and 2017 National Electric Code... approved by the BOS on 8/17/22 and took effect 30 days later."⁵

6. Climate zones 2B, 3B, 4B, 5B for Arizona. VERIFIED (DOE/IECC designation), consistent with the same national climate-zone framework used and cited elsewhere on this site's state pages. 

7. IRC M1401.3 (Manual J equipment sizing requirement). VERIFIED as a stable, standard IRC citation. This section number and its substance are consistent across recent IRC editions, matching the treatment of the same citation on this site's Texas and Colorado pages.

What remains genuinely unconfirmed: the exact energy-code posture (mandatory, voluntary, or absent) for the dozens of Arizona cities, towns, and counties not named on this page; the precise local amendment text each named jurisdiction has layered on top of its base IECC edition; and whether any additional Arizona jurisdiction has, since this research pass, changed its adoption status. A secondary source referenced a January 1, 2026 date for a related Tucson code action; this page relies on Tucson's own current "Building Codes" page language and its July 1, 2026 effective date as the operative statement, and flags the discrepancy here rather than resolving it without a primary source confirming the earlier date's scope. Confirm any of these directly with the relevant building department before finalizing a compliance strategy.

Sources

This page summarizes Arizona's absence of a statewide residential energy code and three jurisdiction-specific adoptions for general guidance. Because Arizona energy code adoption happens jurisdiction-by-jurisdiction under home rule, requirements for any specific city, town, or county not named here may differ. Always confirm current requirements with your local building department before finalizing design or bidding.