McKinney TX Energy Code Multifamily: 2024 IECC, 2026 Amendments, and When to Study First

If you are building multifamily inside the City of McKinney, Texas, you are on the 2024 energy code, and it changed again in October 2026. McKinney adopted the 2024 International Energy Conservation Code with the North Central Texas Council of Governments (NCTCOG) recommended amendments by Ordinance 2025-08-068, adopted August 19, 2025, with the 2024 codes in effect from October 1, 2025. On October 5, 2026 the City Council approved a further IECC ordinance that made commercial energy monitoring elective and cut the off-site renewable energy contract from ten years to one. That puts McKinney with Plano and 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. Teams get caught when they price a 2021 IECC package, copy a Plano filing next door, or carry a ten-year renewable contract into a pro forma that McKinney no longer requires.

This page is the McKinney 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, Arlington Energy Code multifamily, and Plano 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 McKinney Right Now

Per the City of McKinney Building Inspections page and the City's adopted ordinances (primary sources; confirm with the City before you file):

• The City Council approved the 2024 International Energy Conservation Code with amendments as part of the 2024 codes package (IBC, IRC, IPC, IMC, IFGC, IECC, IPMC, ISPSC, and IFC). The City lists the 2024 codes as in effect from October 1, 2025.
• Ordinance 2025-08-068 (Legistar file 25-3063, adopted August 19, 2025, after a unanimous Building and Standards Commission recommendation on July 7, 2025) replaced Sections 122-35 and 122-36 of Chapter 122, Article II of the McKinney Code of Ordinances. Section 122-35 adopts the 2024 IECC. Section 122-36 adopts the NCTCOG Recommended Amendments to the 2024 IECC dated March 2025, intended to comply with the Texas Building Energy Efficiency Performance Standards (Texas Health and Safety Code Section 388.003).
• That ordinance replaced Ordinance 2022-11-124 of November 1, 2022, which had put McKinney on the 2021 IECC from January 1, 2023.
• The October 5, 2026 IECC ordinance (Legistar file 26-0944, recommended unanimously by the Building and Standards Commission on September 14, 2026) rewrote Section 122-36 again. It adopts the NCTCOG March 2025 amendments plus the NCTCOG Special Amendment to the 2024 IECC dated May 2026, and adds two McKinney changes covered below. It takes effect on passage and publication.

In City staff's own summary of the 2024 adoption, required insulation and fenestration R and U values, air leakage, and the Energy Rating Index (ERI) are all more stringent than under the 2021 code McKinney used before. McKinney sits in Collin County, climate zone 3A (warm, humid), the same zone as Plano, Dallas, Fort Worth, and Arlington. Same zone and, in Plano's case, the same edition, but different local amendments. Do not copy a neighboring city's package.

What McKinney Changed in 2026

The two McKinney amendments in the October 2026 ordinance land on the commercial provisions, which is where mid-rise apartments, podium buildings, and the common areas of mixed-use projects are filed:

• Energy monitoring (C405.13) is now elective. The model 2024 IECC makes energy monitoring by load and end-use category mandatory for new buildings, with exceptions. McKinney rewrote the section so new buildings may be equipped to do this to earn additional energy efficiency credits under Section C406.2. City staff cited the cost of monitoring equipment and practical difficulty with common electrical design, especially in large buildings. This continues a McKinney pattern: under the 2021 IECC, the City deleted the energy monitoring section (C405.12) outright.
• Off-site renewable contract (C405.15.2.2) cut to one year. The 2024 IECC commercial provisions require renewable energy, met either with on-site systems such as solar panels or with off-site renewable energy. McKinney kept the requirement but reduced the off-site energy agreement to a duration of one year. Proof of enrollment in a renewable energy plan from a Texas Retail Electric Provider, including one bought through an online marketplace for providers, for a minimum one-year term is deemed sufficient.

That second change is the one to read closely next to Plano. Plano deleted C405.15 renewable energy systems entirely from July 1, 2026. McKinney did not. A McKinney commercial filing still has to show the renewable requirement is met, just with a far shorter off-site contract than the model code asks for.

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. That is where the McKinney renewable and energy monitoring amendments matter, and where the decision between on-site solar and a one-year off-site plan belongs in the study, not on the permit counter.
• Garden-style and townhome projects. Three stories or less usually lands on the residential provisions, with tighter 2024 envelope and air leakage values, duct and envelope testing, and a choice of prescriptive, performance, or ERI paths.

Proof From ECC Studies (Method, Not McKinney Invoices)

ECC does not publish a McKinney or Texas dollar-per-square-foot average, and we do not have a McKinney 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 McKinney 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 McKinney price.

Common Mistakes on McKinney Multifamily Energy Filings

• Pricing a 2021 IECC package. McKinney has enforced the 2024 IECC since October 1, 2025. Dallas and Arlington are still on the 2021 IECC.
• Copying a Plano filing. Plano is also on the 2024 IECC, but it deleted C405.15 renewable energy systems and rewrote its own dwelling unit ventilation rule. McKinney kept the renewable requirement with a one-year off-site option.
• Budgeting a ten-year renewable contract. Since the October 5, 2026 ordinance, McKinney accepts a one-year off-site agreement, including a Texas Retail Electric Provider renewable plan.
• Carrying mandatory energy monitoring costs. C405.13 monitoring is elective in McKinney. Use it only if the credits under C406.2 are worth it for your project.
• Reading old code text. The online codified Chapter 122 can lag the ordinances, and the City lists Chapter 122 as in process of updates. Read the adopted ordinances for your filing date.
• 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 renewable approach, and the testing plan, then the paperwork follows.

When to Study First

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

1. Confirm the permit address is inside the City of McKinney and on the 2024 IECC as amended by Ordinance 2025-08-068 and the October 5, 2026 ordinance 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 the renewable requirement is met: on-site systems or a one-year off-site agreement
4. Decide whether elective energy monitoring earns credits worth buying, or whether other C406 credits are cheaper
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 McKinney energy code for multifamily is the 2024 IECC with NCTCOG amendments, adopted by Ordinance 2025-08-068 and in effect since October 1, 2025. The October 5, 2026 ordinance made commercial energy monitoring elective and cut the off-site renewable agreement to one year, while keeping the renewable requirement that Plano deleted, all in climate zone 3A. This is the McKinney city-code door, not the statewide Texas code-path page, not the Houston, Austin, Dallas, San Antonio, Fort Worth, El Paso, Corpus Christi, Arlington, or Plano city doors, and not the Texas study door. Lock the split, the edition, and the renewable approach first, then buy the paperwork that matches the plan.