Arpit Jain 13 min February 25, 2026

Arizona Energy Code Compliance: A Guide for Commercial & Residential Projects

The Direct Answer: Key Arizona Energy Code Requirements

Arizona does not have a statewide building or energy code. Compliance is dictated by the codes and amendments adopted by individual cities, counties, and towns. Most major jurisdictions, including Phoenix, Tucson, and Chandler, have adopted a version of the International Energy Conservation Code (IECC), typically the 2018 edition, with local amendments.

For professionals, this means you must verify the specific requirements for the project's exact location. Here are the key takeaways for the topics discussed:

• Commercial Tenant Improvements (Chandler): For a TI in Chandler, which uses the 2018 IECC, compliance focuses on the specific systems being altered.
  • Lighting Power Density (LPD): Must meet the LPD values in 2018 IECC Table C405.3.2(1) or C405.3.2(2). For a typical office space, this is 0.79 W/ft² using the Space-by-Space Method.
  • Daylighting Controls: Required in spaces with over 150 watts of general lighting within a sidelit or toplit daylight zone, per IECC §C405.2.4.
  • HVAC Efficiency: New or replacement HVAC units must meet the minimum efficiencies listed in the extensive tables of IECC §C403.3.2.
• Residential Blower Door Tests: A blower door test is mandatory for all new residential construction in jurisdictions that have adopted the 2018 IECC or a later version, including Phoenix and Tucson.
  • Air Leakage Threshold: Both Phoenix and Tucson are in Climate Zone 2. Per 2018 IECC §R402.4.1.2, the maximum air leakage rate is 5.0 air changes per hour at 50 Pascals (ACH50). There is no significant difference in this requirement between the two cities as they both adhere to the base 2018 IECC for this provision.
• Residential Insulation (Phoenix): For new homes in Phoenix (Climate Zone 2), the prescriptive insulation R-values under the 2018 IECC are:
  • Attics/Ceilings: R-38
  • Wood-Frame Walls: R-20 in the cavity OR R-13 in the cavity plus R-5 of continuous insulation on the exterior.

Requirement Area	City of Chandler (Commercial TI)	City of Phoenix (New Residential)	City of Tucson (New Residential)
Governing Code	2018 IECC with local amendments	2018 IECC with local amendments	2018 IECC with local amendments
LPD (Office Space)	0.79 W/ft² (Space-by-Space)	N/A	N/A
Blower Door Test	N/A	Mandatory, ≤ 5.0 ACH50	Mandatory, ≤ 5.0 ACH50
Attic Insulation	N/A	R-38	R-38
Wall Insulation	N/A	R-20 or R-13+5 ci	R-20 or R-13+5 ci

Why Arizona's Energy Code Landscape Matters

The most common pitfall for design professionals working in Arizona is assuming uniformity. Because Arizona is a "home rule" state, each municipality acts as its own authority having jurisdiction (AHJ). A project in Scottsdale may have slightly different requirements than one a few miles away in Phoenix or Tempe. This decentralized system makes it imperative to perform jurisdictional research at the very start of any project.

Here's why this is critical for your workflow:

• Early Design Decisions: Envelope design (insulation, fenestration) and MEP system selection are directly impacted by the locally adopted energy code. Getting this wrong early can lead to costly redesigns.
• Permitting & Plan Review: Plan reviewers in cities like Phoenix and Chandler will specifically check for compliance with their adopted version of the IECC and their local amendments. Submittals must include compliance documentation, such as a COMcheck or REScheck report, which is specific to the code version they enforce.
• Inter-Code Relationships: The energy code (IECC) doesn't exist in a vacuum. It directly coordinates with:
  • International Building Code (IBC): Chapter 13 of the IBC explicitly requires compliance with the IECC.
  • International Mechanical Code (IMC): Dictates requirements for HVAC equipment installation, ventilation, and exhaust, which are tied to energy efficiency.
  • ASHRAE Standards: ASHRAE 90.1 is a referenced standard and an alternative compliance path for commercial buildings under the IECC. ASHRAE 62.1 and 62.2 are key for ventilation calculations that affect energy loads.
  • National Electrical Code (NEC): Governs the installation of lighting controls, occupancy sensors, and other energy-saving electrical devices required by the IECC.

Failing to verify local requirements can lead to plan review rejection, inspection failures, and project delays.

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For a large tenant improvement in an existing commercial shell building in Chandler, what are the specific requirements under the Arizona Energy Code (as amended by the city) for demonstrating compliance? Specifically, what are the thresholds for lighting power density (LPD), mandatory daylighting controls, and HVAC system efficiency that differ from the base IECC?

For a commercial tenant improvement (TI) in Chandler, you must comply with the City of Chandler's adopted 2018 International Energy Conservation Code (IECC) and its local amendments. The city has not significantly amended the core commercial provisions for lighting and HVAC, so the requirements of the base 2018 IECC are the primary guide.

Compliance for a TI falls under IECC Chapter 5 [CE], Existing Buildings. The scope of your work dictates which sections apply. Per IECC §C503 (Alterations), any new equipment or building system must comply with the requirements for new construction.

1. Lighting Power Density (LPD)

If the lighting system is altered, it must meet the LPD requirements of IECC §C405.3. You have two primary compliance paths:

• Building Area Method (Table C405.3.2(1)): This method provides a single LPD value for the entire building type (e.g., Office = 0.82 W/ft²). This is simpler but less flexible for TIs.
• Space-by-Space Method (Table C405.3.2(2)): This is the most common method for TIs. You calculate the LPD for each individual space within your scope. For a typical office TI, key values include:
  • Office - Enclosed: 0.89 W/ft²
  • Office - Open Plan: 0.79 W/ft²
  • Conference/Meeting/Multipurpose: 0.98 W/ft²
  • Corridor: 0.52 W/ft²

Compliance is documented by submitting a COMcheck report with the permit drawings, showing the proposed lighting wattage is less than or equal to the allowed wattage.

2. Mandatory Daylighting Controls

If your TI involves adding or replacing lighting, you must comply with IECC §C405.2.4, Daylight-responsive controls. These controls are required when:

• The space is enclosed.
• The total wattage of general lighting in the daylight zone is 150 watts or more.
• The daylight zone is either sidelit (adjacent to windows) or toplit (under skylights).

The sidelit daylight zone is defined in IECC §C202 as the area extending horizontally from the vertical fenestration to a depth of 15 feet, or to the nearest full-height partition. These controls must be capable of reducing lighting power by at least 50% in response to available daylight.

3. HVAC System Efficiency

If new or replacement HVAC equipment is part of the TI scope, it must meet the minimum efficiency requirements detailed in IECC §C403, Mechanical Systems.

• Efficiency Ratings: The specific requirements are listed in Tables C403.3.2(1) through C403.3.2(12). These tables cover everything from air conditioners and heat pumps to chillers and boilers. For a common rooftop unit (electric air conditioner), you would reference Table C403.3.2(1) to find the required SEER/EER rating based on its cooling capacity.
• Economizers: If a new single-packaged unit is installed, it may require an economizer per IECC §C403.5. In Chandler (Climate Zone 2B), economizers are required for cooling systems with a capacity of 54,000 Btu/h or greater.
• Documentation: The mechanical plans must include an equipment schedule that clearly lists the make, model, and efficiency ratings of all new units to demonstrate compliance. This information is also entered into the project's COMcheck report.

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Under the Arizona Energy Code, when is a blower door test mandatory for new residential construction? Are there specific air leakage (ACH50) thresholds that must be met in Phoenix versus Tucson?

A blower door test is mandatory for all new residential dwelling units in any Arizona jurisdiction that has adopted the 2012 IECC or a more recent version. Both the City of Phoenix and the City of Tucson have adopted the 2018 International Residential Code (IRC) and 2018 IECC, which mandate this testing.

The specific requirement is found in 2018 IECC §R402.4.1.2 (Testing) and IRC §N1102.4.1.2. This section states that the building or dwelling unit "shall be tested and verified as having an air leakage rate not exceeding five air changes per hour in Climate Zones 1 and 2, and three air changes per hour in Climate Zones 3 through 8."

• Phoenix and Tucson Threshold: Both Phoenix and Tucson are located in Climate Zone 2. Therefore, the mandatory air leakage threshold for new homes in both cities is the same: not to exceed 5.0 air changes per hour at 50 Pascals (ACH50).
• Reporting: The verified test results must be reported to the building official and are typically documented on a certificate or sticker posted inside the electrical panel of the home. This is a required step for passing final inspection and obtaining a Certificate of Occupancy.
• Exceptions: There are very few exceptions. The test is required for the complete thermal envelope of the new home. Alterations or additions to existing homes may also trigger this requirement depending on the scope of work and local amendments, but it is always required for new construction.

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What are the insulation R-value requirements for attics and walls in Phoenix for new homes?

For new homes built in Phoenix, the insulation requirements are dictated by the City of Phoenix's adoption of the 2018 International Energy Conservation Code (IECC). Phoenix is in Climate Zone 2. The prescriptive R-value requirements are found in Table R402.1.2, Insulation and Fenestration Requirements by Component.

Here are the specific minimum R-values for Phoenix:

• Ceilings/Attics:

  • The prescriptive requirement is R-38. This applies to the entire ceiling area that forms part of the thermal envelope.

• Wood-Frame Walls:

  • There are two common prescriptive paths for walls:
    1. R-20 cavity insulation (e.g., filling a 2x6 wall cavity with R-20 batt insulation).
    2. R-13 cavity insulation PLUS R-5 of continuous insulation (ci) installed on the exterior of the sheathing. The "R-13+5" approach provides a thermal break and often results in better real-world performance.

• Mass Walls (e.g., CMU):

  • R-8 on the interior or exterior of the wall.

Prescriptive R-Value Table for Phoenix (Climate Zone 2)

Building Component	2018 IECC Prescriptive Requirement
Ceiling	R-38
Wood Frame Wall	R-20 or R-13+5 ci
Mass Wall	R-8
Floor	R-13
Slab Edge	R-10 (for heated slabs only)
Basement Wall	R-5/13 (continuous/cavity)

It is important to note that these are prescriptive values. A builder or designer can also use alternative compliance paths, such as the Total UA Alternative (IECC §R402.1.4) or the Simulated Performance Alternative (IECC §R405), which allow for trade-offs (e.g., using better windows to compensate for slightly less wall insulation). These paths require a REScheck software report to be submitted with the permit documents to prove overall compliance.

Jurisdictional Variations Across Arizona

The "home rule" nature of Arizona means energy code requirements can vary significantly based on climate. While the major metropolitan areas of Phoenix and Tucson are in hot Climate Zone 2, other parts of the state have vastly different needs.

• Flagstaff (Climate Zone 5 - Cold): The City of Flagstaff has adopted the 2018 IECC with significant local amendments to address its cold climate.

  • Air Leakage: The ACH50 limit is 3.0, not 5.0 as in Phoenix.
  • Attic Insulation: R-49 is required, compared to R-38 in Phoenix.
  • Wall Insulation: R-20 + R-5 ci is a common requirement, reflecting the need for higher performance.
  • Foundations: Insulated foundations (R-15 continuous) are required due to the cold ground temperatures.

• Yuma (Climate Zone 2 - Hot): Yuma County generally follows the 2018 IRC/IECC, with requirements very similar to Phoenix and Tucson (R-38 ceilings, R-13 walls, 5.0 ACH50).

This highlights the absolute necessity of verifying the adopted code and local amendments for every project location. Never assume the requirements in one Arizona city apply to another.

Compliance Documentation and the Plan Review Process

To obtain a building permit in most Arizona jurisdictions, you must submit clear documentation demonstrating energy code compliance. Simply drawing the insulation on the plans is not enough.

Commercial Projects (e.g., Chandler, Phoenix):

• COMcheck Report: A complete COMcheck report is required. It must be specific to the adopted code (e.g., "2018 IECC"). The report summarizes the envelope, lighting, and mechanical systems and provides a pass/fail result. The signed report must be included in the construction documents.
• Drawings: Architectural and MEP drawings must align with the COMcheck report.
  • Wall, roof, and floor assembly details must clearly specify all layers and R-values.
  • The lighting plan must include a fixture schedule showing wattage.
  • The mechanical plan must include an equipment schedule with efficiency ratings (SEER, EER, etc.).

Residential Projects (e.g., Phoenix, Tucson):

• REScheck Report: Similar to COMcheck, a REScheck report is the standard for showing compliance, whether using the prescriptive or performance path.
• Drawings: The architectural plans must show:
  • Insulation R-values for all thermal envelope components (walls, ceiling, floors).
  • Window and door U-factors and Solar Heat Gain Coefficients (SHGC).
  • A note specifying the air leakage testing requirement (e.g., "Air leakage rate not to exceed 5.0 ACH50 when tested per ASTM E779").

Plan reviewers will cross-reference your drawings with your COMcheck/REScheck report. Any discrepancy is a common reason for permit rejection.

Frequently Asked Questions (FAQ) about the Arizona Energy Code

1. Does Arizona have a statewide energy code? No. Arizona is a "home rule" state, meaning each city, town, and county adopts and enforces its own set of building and energy codes. You must check with the local building department for every project.

2. What are COMcheck and REScheck, and are they required? COMcheck (for commercial) and REScheck (for residential) are free software tools from the U.S. Department of Energy that simplify energy code compliance analysis. Most Arizona jurisdictions require a signed COMcheck or REScheck report to be submitted with the permit application.

3. What is the most common energy code version used in Arizona? The 2018 IECC is currently the most widely adopted version in major municipalities like Phoenix, Tucson, Mesa, Chandler, and Scottsdale. However, some jurisdictions may be on older or newer cycles, so always verify.

4. How does ASHRAE 90.1 relate to the IECC in Arizona? Per IECC §C401.2, commercial buildings can demonstrate compliance by following ASHRAE Standard 90.1 instead of the IECC. It is a recognized alternative compliance path often used by mechanical engineers for complex projects.

5. Do I need a blower door test for a home addition? This depends on the local jurisdiction and the scope of the addition. Per IRC §N1107.4.2, additions constituting a substantial increase in conditioned floor area may trigger testing requirements for the entire dwelling. Always confirm with the local building official.

6. Do solar panels let me bypass insulation requirements? No. Prescriptive envelope requirements (insulation, air sealing) must be met first. Solar photovoltaic (PV) systems can be used as a credit in the performance-based compliance path (IECC §R406, Energy Rating Index), which can allow for trade-offs in other areas, but they do not eliminate the base requirements for a well-built thermal envelope.

7. Who enforces the energy code in Arizona? The local building department (the Authority Having Jurisdiction or AHJ) for the city or county where the project is located. This includes plan review before the permit is issued and field inspections during construction.

8. Are there local utility rebates for exceeding the energy code? Yes, often. Major utilities in Arizona, like Arizona Public Service (APS) and Salt River Project (SRP), frequently offer incentive programs and rebates for builders who construct homes and buildings that significantly outperform the minimum energy code requirements.