Keeping Up with 2025 Commercial HVAC Code Changes, A Checklist

Permitting moves faster when your drawings match the latest code language. In 2025, many jurisdictions are adopting the 2024 code cycle, federal rules are tightening refrigerant and efficiency requirements, and owners are asking for better air quality without runaway energy bills. Adoption timing varies by state and city, so begin every project by asking your AHJ exactly which editions and local amendments apply to the permits you plan to file this quarter. This guide translates the biggest shifts into a practical checklist you can use right away.

First, what changed in the landscape

• Many cities and states are moving to the 2024 International Energy Conservation Code for commercial buildings, with more emphasis on commissioning, controls, efficiency credits, and documented performance.
• ASHRAE 90.1-2022 is a common compliance path in this cycle, with new prescriptive details and a Mechanical System Performance Path for flexibility.
• A2L refrigerants and related safety provisions are embedded in the 2024 mechanical codes, which reference UL 60335-2-40 for equipment certification and detail detection, ventilation, and electrical needs.
• EPA HFC technology transition rules begin restricting high-GWP refrigerants in new systems on January 1, 2025, by sector and subsector. Product selection and submittal notes need to reflect low-GWP options and the correct effective dates.

Loop in commercial mechanical contractors during schematic design to confirm local code adoption dates, A2L safety provisions, and economizer thresholds before you lock the basis of design.

Your quick code checklist for 2025 projects

• Confirm adopted code editions with your AHJ, for example 2024 IECC and 2024 IMC, and list local amendments on your cover sheet.
• If you use ASHRAE 90.1 for compliance, identify the edition on the energy form, most commonly 90.1-2022 in this cycle.
• Specify equipment and refrigerants that meet 2025 HFC transition rules and local A2L provisions, including detection, exhaust, and electrical requirements.
• Include commissioning scope, responsible party, test points, and owner training deliverables.
• Add fault detection and diagnostics to packaged equipment and economizers where required.
• Attach sequences of operation, O&M manuals, and trend points so commissioning is fast and verifiable.

Energy code updates that will affect your submittals

Require commissioning, clearly. Define the commissioning agent, systems covered, functional tests, and owner training. This avoids late review comments and aligns the team on what “done” looks like.

Show fault detection and diagnostics. Call out required sensors and the logic that will alarm when dampers fail to modulate, economizers do not engage, or refrigerant circuits drift from expected performance. Reviewers want to see how a fault becomes a visible alarm.

Plan how you will earn efficiency credits. If your jurisdiction uses an IECC credit menu, list which credits you are taking and where they appear on drawings. This prevents last-minute point hunting.

If you choose ASHRAE 90.1, note the 2022 changes. Expect expanded economizer requirements, updated baselines, and the option to use total system performance for flexibility. Show on plans how your sequences support these updates.

Ventilation and indoor air quality, what reviewers look for now

Ventilation rates and filtration still track your adopted code and ASHRAE 62.1, but many owners and agencies now ask how you will operate during periods of elevated infection risk. If the owner wants that capability, outline a simple “risk mode” that combines outdoor air, higher filtration, and approved air cleaning, along with who decides to enable it and how alarms are handled.

Checklist items for IAQ

• Call out filter MERV rating and where pressure sensors report loading to the BAS.
• Show clean air devices, if used, in the control sequence so they do not fight the ventilation set point.
• Provide a one-page plan for switching in and out of risk mode, including roles and communication.

Refrigerants, the A2L shift and 2025 HFC rules

Design for A2L from the start. Group A2L refrigerants are low toxicity and mildly flammable. They require certified equipment, defined leak detection, exhaust and alarm response, and certain electrical safeguards. Put detector set points, exhaust rates, and power interlocks directly on schedules and details so safety provisions are visible. Show detector set points, exhaust rates, and electrical clearances on the drawings so the field crew can complete A2L-compliant hvac installation without inspection delays.

Know the 2025 restrictions. Beginning January 1, 2025, new equipment in several categories cannot use high-GWP HFCs. Coordinate with manufacturers on which refrigerants are listed, when product lines change, and how that affects lead times and weights on your lift plans.

Mind efficiency baselines. Federal minimum efficiency steps that took effect in 2023 continue to apply, and small three-phase equipment categories under 65,000 Btu per hour see updated minimums as new models ship. Note the current federal tier and test method on your submittal.

Controls and metering that help you comply and operate better

Controls are where codes and daily operations meet. Trend points should match your commissioning tests so the CxA can prove sequences work and hand the owner a usable dashboard. A seasoned commercial hvac company can translate your chosen IECC or ASHRAE 90.1 path into clear sequences, trend points, and FDD alarms that reviewers approve quickly.

Put these in your sequence and points list

• Mixed air, outdoor air, and return air temperatures for economizer verification.
• Damper position, supply fan speed or static pressure, and compressor staging or inverter speed.
• Filter differential pressure with an alarm threshold and a “return to normal” notification.
• Space temperature, humidity, and dew point where humidity control is required.
• Occupancy or CO₂ signals for demand-controlled ventilation.
• A monthly auto-report to the owner that lists alarm counts, economizer hours, and average supply temperature reset range, so they see the benefits without digging into the BAS.

Documentation that saves time during review

• Commissioning plan. Names the agent, scope, test points, and owner training outline. Reviewers care because it proves there is a path from “installed” to “working as intended.”
• Sequences of operation. Plain-language modes, safeties, resets, and set points on their own sheet. Reviewers care because it lets them align code intent with your logic without guessing.
• O&M packets. Refrigerant type, detector settings for A2L systems, and replacement filter specs. Reviewers care because it shortens the turnover and reduces RFIs after occupancy.
• Energy compliance form. States whether you are using IECC with credits or ASHRAE 90.1 performance, and shows how your design meets the chosen path. Reviewers care because it locks the project to one clear compliance route.
• Tie the commissioning handoff to an hvac service agreement that covers seasonal sensor calibration and FDD support, keeping the building compliant after occupancy.

Common pitfalls you can avoid in 2025

• Calling for legacy refrigerants in new equipment that no longer qualifies under the 2025 transition rules.
• Omitting A2L provisions, such as detector placement and exhaust rates, from plan notes and equipment schedules.
• Assuming the commissioning exemption still applies to your project size, then getting a correction request late in review.
• Leaving economizer and FDD logic fuzzy, which can cause the BAS submittal to bounce.

A simple action plan for the next project

1. Ask your AHJ which code editions and amendments apply to permits submitted this quarter, then list them on the cover sheet.
2. Pick your energy path early, either IECC with credits or ASHRAE 90.1-2022, and design to that path without mixing assumptions.
3. Confirm refrigerants and equipment listings with vendors, and show A2L safety measures on plans to avoid resubmittals.
4. Write the commissioning plan with test points and owner training, and align BAS sequences and trend logs so tests are quick.
5. Bundle a one-page IAQ plan that spells out filtration levels and how you would operate in an infection-risk mode if the owner requests it.

Keeping up with code is less about memorizing chapter numbers and more about building a repeatable process your team can follow on every job. If you want a second set of eyes, Climico can review your drawings for 2025 compliance, flag refrigerant and commissioning gaps, and set up BAS trend templates that make inspections painless.