You submitted the plans. You ran the COMcheck. You got the compliance certificate. And then the building department sent it back.
It happens more than it should — and almost always for the same handful of reasons. After reviewing hundreds of commercial COMcheck submissions, we've seen the same errors delay projects across every building type and jurisdiction.
Here's what's actually causing your COMcheck to fail plan review, and exactly what to do about it.
Why COMcheck failures are more common than architects expect
COMcheck looks straightforward on the surface. But the software is only as accurate as the data entered into it — and the gap between what's on the drawings and what the building department needs to see in the compliance report is where most failures happen.
A rejected COMcheck doesn't just mean a resubmission. It means a delayed permit, a frustrated contractor, and a client asking why things are behind schedule. The good news: every one of these failures is preventable.
Reason 1: Wrong IECC code cycle for the jurisdiction
This is the single most common reason COMcheck reports get kicked back — and the most avoidable.
The United States does not have a single, uniform energy code. Each state adopts its own version of the International Energy Conservation Code (IECC) on its own timeline, and local jurisdictions can lag behind state adoption by years. What your neighboring county enforces may be a full code cycle behind what the building department across the city line requires.
To make it worse, some jurisdictions have local amendments on top of the state-adopted code. New York City, for example, enacted its own 2025 NYCECC — based on the 2024 IECC — for all permit applications filed on or after March 30, 2026. Running your COMcheck on the 2021 IECC for a NYC project filed after that date will get your report rejected outright.
How to fix it: Before you open COMcheck, confirm the adopted code with the local Authority Having Jurisdiction (AHJ) — not the state energy office, not a code database. Call the building department directly. Ask which IECC cycle and which version of ASHRAE 90.1 they are currently accepting. When in doubt, ask if they have a current preference in writing.
Reason 2: Incorrect or estimated envelope inputs
COMcheck's envelope compliance section requires precise inputs: assembly U-factors, continuous insulation R-values, window U-factors, and Solar Heat Gain Coefficients (SHGC) for every fenestration type on the project. When these values are estimated — or pulled from a previous project without verification — the report fails.
The most common envelope mistakes we see:
- Using nominal R-values instead of whole-assembly U-factors. A 2×6 wall with R-19 batt does not have a whole-assembly U-factor that corresponds directly to R-19. Framing, air gaps, and sheathing all affect the calculation.
- Generic window values instead of manufacturer-specified ratings. "Double pane" is not a COMcheck input. You need the NFRC-rated U-factor and SHGC from the actual specified product — or a conservative substitute that the AHJ will accept.
- Missing continuous insulation. If your wall assembly includes a layer of continuous insulation, it must be entered separately from the cavity insulation. COMcheck treats them differently.
How to fix it: Use manufacturer product data sheets and NFRC ratings for all fenestration. For opaque assemblies, use the COMcheck-compatible U-factor tables in the IECC or ASHRAE 90.1 appendices, or calculate whole-assembly U-factors using ASHRAE's parallel-path method.
Reason 3: Lighting power density errors
Lighting compliance is where architects most frequently hand off the COMcheck to someone who wasn't involved in the lighting design — and where the most consequential errors happen.
COMcheck offers two lighting compliance paths: the Building Area Method and the Space-by-Space Method. Choosing the wrong method for your project, or mixing inputs between them, will produce a report that either falsely passes or fails when it shouldn't.
Common lighting errors:
- Using building area type that doesn't match the actual occupancy. "Office" and "healthcare" have very different allowable lighting power densities. A medical office entered as a generic office will likely pass COMcheck — and fail plan review when the reviewer looks at the occupancy on the drawings.
- Forgetting to include exterior lighting. Parking lots, facades, and canopies all have separate power allowances in COMcheck. Omitting them is a common oversight that reviewers catch.
- Lighting controls not documented. Many jurisdictions require that automatic shut-off controls, daylight controls, and occupancy sensors be listed in the COMcheck report. A passing watts-per-square-foot number doesn't substitute for the controls documentation.
How to fix it: Run COMcheck's lighting section from the actual reflected ceiling plan, not from a fixture schedule alone. Confirm the space-by-space occupancy classifications with the drawings and match them to the intended use. Have the lighting designer or electrical engineer review the COMcheck inputs before submission.
Reason 4: Mechanical systems not fully documented
Mechanical compliance in COMcheck covers HVAC equipment efficiency, service water heating, and in some jurisdictions, ventilation controls. This section is frequently left incomplete — either because the mechanical engineer hasn't finalized equipment selections, or because the architect submitting the COMcheck doesn't have access to the full mechanical schedule.
Submitting a COMcheck before mechanical selections are confirmed is one of the leading causes of plan review rejection and subsequent re-submittal fees.
Specific things reviewers flag:
- Placeholder equipment efficiency values. If you enter a gas furnace with a generic AFUE or a chiller with a default COP, plan reviewers who check will catch it. COMcheck inputs must match specified equipment.
- Missing service water heating. Commercial projects with any hot water demand — restaurants, gyms, hotels, medical facilities — require water heating inputs. Omitting this section entirely is a surprisingly common oversight.
- Split systems entered as single units. Multi-zone VRF systems and split DX systems have specific entry requirements in COMcheck. Entering them incorrectly produces a compliance result that doesn't reflect the actual system.
How to fix it: Don't submit COMcheck until mechanical equipment has been selected and the mechanical engineer has reviewed the inputs. If you're in early permit with preliminary equipment specs, flag this clearly in the submission and be prepared for conditions on the mechanical approval.
Reason 5: Climate zone mismatch
COMcheck is climate zone-sensitive. Enter the wrong climate zone and every envelope and mechanical threshold in the report is calculated against the wrong standard. Your project could show a comfortable compliance margin — and still fail because the thresholds applied were for a different location entirely.
Climate zone errors typically come from:
- Using the project's state rather than the specific county or municipality. Climate zones in the US are defined by county. A state like California spans zones 1 through 16. Texas spans multiple IECC climate zones. Using the state-level default when COMcheck prompts for location is an error.
- Outdated climate zone maps. The 2021 IECC updated several county-level climate zone assignments from the 2018 version. If your COMcheck template was set up for a prior code cycle and the climate zone was pre-populated, verify it against the current IECC climate zone map before submitting.
How to fix it: Enter the full project address in COMcheck and let the software assign the climate zone automatically. Then cross-check the assigned zone against the current IECC climate zone map for your jurisdiction before finalizing the report.
A note on the plan review process itself
Even a technically correct COMcheck can create friction at plan review if the documentation doesn't clearly connect back to the drawings. Reviewers are looking to verify that what's in COMcheck matches what's on the plans — and if that connection requires too much interpretation on their part, expect comments.
Best practice: include a COMcheck compliance narrative as a cover sheet that maps each input category (envelope, lighting, mechanical) to the relevant drawing sheet. This is not required by code, but it dramatically reduces the back-and-forth with plan reviewers.
Free COMcheck consulting — before you submit
If any of this sounds familiar, or if you're looking at a COMcheck that isn't passing and aren't sure why, we offer free consulting for COMcheck submissions.
We'll review your current report, identify what's causing the failure or creating compliance risk, and walk you through exactly what needs to change — at no cost, no commitment.
For projects that need full COMcheck documentation, our fixed-fee service starts at $150 for projects up to 10,000 ft², with turnaround in 1–2 business days. Minor revisions and plan review response support are included.
Get your free COMcheck consultation
www.InversEnergy.com