Plano TX Energy Code Multifamily: 2024 IECC, Local Amendments, and When to Study First

If you are building multifamily inside the City of Plano, Texas, you are on a newer code than most of North Texas. Plano adopted the 2024 International Energy Conservation Code with local amendments by Ordinance 2025-6-10, passed June 9, 2025 and effective August 1, 2025. That puts Plano with Austin on the 2024 edition, while Dallas, Arlington, Houston, San Antonio, and El Paso sit on the 2021 IECC and Fort Worth and Corpus Christi on the 2015 IECC. Plano then trimmed the 2024 text: it deleted the residential additional efficiency section (R408), deleted the dwelling unit lighting and switched receptacle controls section, rewrote the energy recovery ventilation rule for apartments, and in 2026 deleted the commercial renewable energy section. Teams get caught when they price a 2021 IECC package, copy a Dallas or Austin filing, or design to 2024 sections Plano removed.

This page is the Plano Energy Code door for multifamily developers. For the statewide Texas commercial code path (the 2015 IECC floor, ASHRAE pairings, and why mid-rise is not HERS-first), see ASHRAE COMcheck Texas multifamily. For the Texas study door, see energy code feasibility study Texas. Other Texas city doors already live: Houston Energy Code multifamily, Austin Energy Code multifamily, Dallas Energy Code multifamily, San Antonio Energy Code multifamily, Fort Worth Energy Code multifamily, El Paso Energy Code multifamily, Corpus Christi Energy Code multifamily, and Arlington Energy Code multifamily. Program, testing, and modeling context: ENERGY STAR Multifamily New Construction, blower door testing for multifamily buildings, and multifamily energy modeling.

What Code Applies in Plano Right Now

Per the City of Plano Building Codes & Ordinances page and the City's adopted ordinances (primary sources; confirm with the City before you file):

• Ordinance 2025-6-10 repealed Ordinance 2022-1-15 (the 2021 IECC, adopted January 24, 2022) and adopted the 2024 IECC with additions, deletions, and amendments as Article XVIII, Energy Conservation Code, of Chapter 6 of the Plano Code of Ordinances. It was passed June 9, 2025 and took effect August 1, 2025, as part of the City's 2024 codes package.
• The amendments are in Section 6-686. Read them for your filing, not a generic 2024 IECC summary.
• Ordinance 2026-5-3, passed May 11, 2026 and effective July 1, 2026, deleted Section C405.15 "Renewable energy systems" in its entirety, after a Building Standards Commission hearing on April 21, 2026.

Plano sits in climate zone 3A (warm, humid), the same zone as Dallas, Fort Worth, and Arlington. Same zone, newer edition, different amendments. Do not copy a neighboring city's package.

What Plano Changed in the 2024 IECC

The local amendments that matter most on apartment and mixed-use work:

• Energy recovery for dwelling units (C403.7.4.1). Plano rewrote the rule for nontransient dwelling units on the commercial provisions. The system must meet either an enthalpy recovery ratio of at least 50% at cooling design and 60% at heating design, or a sensible recovery efficiency of at least 65% at 32 degrees F with net moisture transfer of at least 40% at 95 degrees F in climate zones 0A, 1A, 2A, and 3A (rated to CAN/CSA C439). Plano's exceptions include units of 500 square feet or less of conditioned floor area in climate zone 3, heating-side enthalpy in zones 0 to 2, and, in Plano's text, dwelling units using ventilation systems per the fan efficacy table in R406 are considered in compliance.
• Dwelling unit lighting and receptacle controls (C405.2.10) deleted. The 2024 sleeping unit and dwelling unit lighting and switched receptacle control section does not apply in Plano.
• Renewable energy systems (C405.15) deleted effective July 1, 2026 by Ordinance 2026-5-3.
• Alternative compliance (C104.1.2 and R104.1.2). A building certified by a national, state, or local accredited energy efficiency program and determined by the Energy Systems Laboratory to comply may, at the code official's option, be considered in compliance, and EPA ENERGY STAR certification of energy code equivalency is considered in compliance. On the residential side, each one- and two-family dwelling must still be tested for air and duct leakage regardless of program or path.
• Residential additional efficiency (R408) deleted in its entirety, and interior lighting controls (R404.2) and the solar-ready system (R105.2.2) section deleted.
• Energy Rating Index (Table R406.5), climate zone 3: maximum ERI 57 (not including on-site power production) from September 1, 2025 to August 31, 2028, then 55 from September 1, 2028.
• Envelope details: an attic roofline option for air-impermeable insulation when mechanical equipment and ducts are entirely inside the thermal envelope, a slab-edge insulation exception where the code official designates moderate to heavy termite probability, and field air-sealing allowed for electrical boxes in lieu of NEMA OS 4 boxes.

The City's 2024 Residential Energy Code Compliance Certificate (form FM624RY059, revised February 18, 2026) lists five residential paths: prescriptive, simulated performance, ERI, ENERGY STAR Certified Homes, and Texas HB 3215 (87R) HERS Index compliance. It records duct leakage in CFM25 per system and envelope leakage in ACH50 or CFM per square foot of dwelling unit enclosure, tested by a third party approved by the building official.

Residential vs Commercial Split for Multifamily

The 2024 IECC draws the line by building type and height. Group R-2, R-3, and R-4 buildings three stories or less above grade plane fall under the residential provisions. Taller apartment buildings, and the nonresidential portions of any building, fall under the commercial provisions, where the 2024 IECC commercial chapter or its ASHRAE 90.1-2022 alternative applies.

• Mid-rise, podium, and mixed-use projects. Retail, amenity, lobby, corridor, and parking areas follow commercial documentation, and the Plano ERV rule for dwelling units sits on the commercial side. Decide early whether units meet the ERV ratios or use the R406 fan efficacy exception.
• Garden-style and townhome projects. Three stories or less usually lands on the residential provisions, with envelope tables, air and duct leakage testing, and one of the paths on the City's compliance certificate.

Proof From ECC Studies (Method, Not Plano Invoices)

ECC does not publish a Plano or Texas dollar-per-square-foot average, and we do not have a Plano energy-code invoice to present as your number. We cite other studies as proof of method, and we label them that way.

On our 267-unit Cromwell, CT study (CS68), two buildings up to six stories (272,036 square feet) were filed on IECC commercial provisions using ASHRAE 90.1-2019 Appendix G. The recommended all-electric tier came in at about $35.23 per square foot net and captured a $1,500 per unit Energize CT incentive ($400,500). Those are Connecticut outcomes on an earlier ASHRAE year, not Plano invoices. They show the order: lock the path and edition, rank the packages, then document the winner.

On a 112-unit Revere, MA study (CS57), a seven-story mixed-use building kept dwelling units on a Massachusetts Stretch HERS path and still called for a COMcheck report for all common and support areas, plus ASHRAE 62.1 ventilation calculations and lighting power density calculations. The recommended ductless package landed at about $42.52 per square foot net. Those are Massachusetts outcomes. We cite them as proof that mixed-use paperwork splits before modeling hours, not as a Plano price.

Common Mistakes on Plano Multifamily Energy Filings

• Pricing a 2021 IECC package. Plano has enforced the 2024 IECC since August 1, 2025. Dallas and Arlington next door are still on the 2021 IECC.
• Copying an Austin filing. Austin is also on the 2024 IECC, but with its own appendices and amendments. Plano deleted R408, C405.2.10, and C405.15, and rewrote C403.7.4.1.
• Designing to deleted sections. Budgeting for renewable energy systems under C405.15 or R408 additional efficiency credits adds cost the Plano code does not require.
• Missing the ERV rule. Mid-rise dwelling units on the commercial provisions need compliant energy recovery ventilation or the R406 fan efficacy exception. That choice moves mechanical rooms, shafts, and budgets.
• Using last cycle's ERI target. The climate zone 3 maximum is 57 through August 31, 2028, then 55.
• Buying COMcheck or ERI hours before the path is locked. The study should settle residential vs commercial, 2024 IECC vs ASHRAE 90.1-2022 for commercial areas, the ventilation approach, and the testing plan, then the paperwork follows.

When to Study First

Settle the Plano path before anyone buys REScheck, COMcheck, ERI, or whole-building modeling hours:

1. Confirm the permit address is inside the City of Plano and on the 2024 IECC as amended by Ordinances 2025-6-10 and 2026-5-3 for your filing date
2. Lock the residential vs commercial split (three stories or less for Group R-2 / R-3 / R-4 on the residential provisions, and commercial documentation for nonresidential areas)
3. For each commercial portion, pick 2024 IECC commercial or ASHRAE 90.1-2022, and decide how dwelling units meet Plano's C403.7.4.1 energy recovery rule
4. For residential portions, pick a path from the City's compliance certificate and plan air and duct leakage testing with an approved third party
5. Model envelope, window, ventilation, and HVAC packages side by side for climate zone 3A, including ENERGY STAR Multifamily New Construction where you plan to enroll
6. Produce the COMcheck reports, performance models, and test results against the locked plan

That comparison is what a free feasibility study produces. For the Texas study method, see energy code feasibility study Texas. For how modeling works on apartment buildings in general, see multifamily energy modeling. If the path is already chosen and you need COMchecks, modeling, inspections, or testing, see ECC services.

Bottom Line

The Plano energy code for multifamily is the 2024 IECC with local amendments, adopted by Ordinance 2025-6-10 and effective August 1, 2025, with C405.15 renewable energy systems deleted from July 1, 2026 by Ordinance 2026-5-3. Plano rewrote the energy recovery rule for dwelling units, deleted R408 and the dwelling unit lighting control section, and steps the climate zone 3 ERI down to 55 in 2028, all in climate zone 3A. This is the Plano city-code door, not the statewide Texas code-path page, not the Houston, Austin, Dallas, San Antonio, Fort Worth, El Paso, Corpus Christi, or Arlington city doors, and not the Texas study door. Lock the split, the edition, and the ventilation approach first, then buy the paperwork that matches the plan.