COMcheck submittals that get sent back for revision typically aren't failing because of a calculation error — they're failing because of a handful of recurring input and classification mistakes that are avoidable with closer attention before submitting. Commercial projects tend to be more complex than residential ones, which means there are more places for these mistakes to creep in.
Running a COMcheck report against IECC when the jurisdiction has adopted ASHRAE 90.1, or vice versa, produces a result that doesn't reflect the actual applicable standard. This mistake is more common than it should be, particularly for contractors working across multiple jurisdictions with different adopted baselines, and it's one of the first things worth double-checking before running any calculation.
Lighting power density allowances and some envelope requirements vary by space-use classification, and applying a generic or incorrect classification — treating a restaurant space as generic retail, for instance — can produce a lighting compliance result that doesn't match the actual applicable allowance for that space type.
COMcheck lighting compliance is sensitive to the specific fixtures and wattages proposed, and a common mistake is running the report against an earlier lighting design that doesn't match the final lighting plan submitted elsewhere in the permit package. Even modest changes to fixture selection between design phases can shift a marginal lighting result.
On projects involving an addition to an existing commercial building, submittals sometimes evaluate only the new envelope area inconsistently, or fail to clearly separate what's new construction from what's existing — creating ambiguity for a reviewer trying to confirm the compliance boundary.
Where mechanical efficiency factors into commercial compliance, using a generic or default equipment assumption rather than the actual specified system is a common gap — particularly on projects where the mechanical design was still being finalized when the COMcheck report was first run, and the report wasn't updated afterward.
How do I confirm whether my jurisdiction uses IECC or ASHRAE 90.1?
Check with the local building department directly — adoption varies by state and sometimes by local jurisdiction within a state, so it shouldn't be assumed based on a different project.
What's the most common reason a COMcheck lighting section gets flagged?
Misclassified space use or an outdated lighting plan that doesn't match the final design — both are documentation issues rather than calculation errors.
Does a COMcheck rejection typically require redoing the whole report?
Usually not — most rejections involve correcting specific inputs rather than starting over, but each correction cycle still adds time to the permit timeline.
Psychro.Pro builds COMcheck reports checked against the correct code baseline, accurate space-use classifications, and your final lighting and mechanical plans.Learn more.
