Air Balance Report: What to Include and How to Use It

An air balance report documents how a HVAC system was operating when it was tested: the airflow measured at supply, return, and exhaust points; the readings used for comparison; adjustments made; and the final condition of the system. A useful report makes the work reviewable. It should let a technician, project manager, and customer see what was found, what changed, and whether any remaining issue needs follow-up.

For routine service work, the report does not need to be complicated. It does need a clear system identifier, dated readings, target or design values when available, equipment settings, adjustment notes, and a sign-off record.

Use an air balance report when: commissioning a new or altered system, investigating uneven temperatures or comfort complaints, documenting airflow-related repairs, or verifying work before turnover.

What an air balance report is—and is not

An air balance report is the job record for testing and adjusting airflow through a system. It commonly covers air-handling equipment, ducts, grilles and registers, returns, exhaust devices, and related controls.

The report is not simply a list of room airflow readings. Readings without equipment details, test conditions, targets, or notes about adjustments leave too much unanswered. For example, a supply register may have a measured airflow value, but that value is hard to interpret if the fan setting, filter condition, damper position, or intended airflow is not recorded.

The level of detail should match the job scope:

• Service diagnostic report: Documents conditions found, selected measurements, suspected restrictions or distribution issues, work performed, and recommended next steps.
• Balancing report for an installation or renovation: Records equipment and terminal readings before and after adjustment, plus deviations and unresolved items.
• Turnover or project closeout report: Organizes the final readings and supporting notes required by the customer, project documents, or applicable project requirements.

If the work requires a particular report format, acceptance procedure, credential, or independent verification, confirm that requirement before testing. Do not represent a standard service worksheet as a formal project certification unless it meets the stated project requirements.

Start with the job, system, and test conditions

The first section should establish exactly what was tested. This avoids confusion later when a site has multiple systems, zones, or similar-looking equipment.

Include:

• Customer name and site address
• Job number and date
• Technician or test team
• System type and equipment tag or identifier
• Areas, zones, or rooms included in the scope
• Reason for the test: complaint, repair verification, startup, renovation, closeout, or maintenance
• Work order, proposal, drawing, or equipment schedule reference, if available
• Start and finish times

Then document the conditions that could affect results. Use plain language and record only what is relevant to the work.

Examples include:

• Thermostat mode and setpoint
• Fan operating mode or speed setting
• Whether the system had reached a stable operating condition before readings were taken
• Filter condition or whether filters were replaced before testing
• Outdoor-air, return-air, exhaust, or relief-air settings when those are part of the scope
• Damper, diffuser, grille, and register positions at the time of testing
• Doors, windows, or other openings that materially affected the test area
• Temporary obstructions, closed rooms, construction activity, or access limitations

A short condition note is often more useful than a long narrative. For example: “System operating in cooling; fan set to normal operating speed; all served room doors open; two ceiling diffusers inaccessible above finished storage racks.”

Record the target before judging the result

A measured airflow reading only becomes a pass, fail, or follow-up item when it is compared with an appropriate target.

Targets may come from approved project documents, equipment data, a prior verified baseline, room requirements supplied by the customer, or the service scope. Identify the source in the report instead of leaving a column labeled “target” without context.

If no target is available, do not manufacture one. Report the reading as observed and state that a target was not provided or could not be confirmed. You can still identify imbalances within the system, such as a supply total that does not reasonably align with the return path, but distinguish that field observation from a formal acceptance determination.

A practical terminal-airflow table might include:

Use a consistent unit within each table. If different tests require different units or methods, label them clearly rather than combining them in one unmarked column.

Document the equipment measurements that explain terminal readings

Terminal readings alone may not show why a system is underperforming. The report should include the equipment-level observations needed to interpret the results.

For the applicable equipment, consider recording:

• Air handler, furnace, fan coil, rooftop unit, or ventilator identifier
• Fan setting, drive setting, controller setting, or other relevant operating position
• Supply, return, outdoor, exhaust, and relief airflow readings where included in the scope
• Filter condition
• Coil condition when it affects the service findings
• Damper positions and actuator condition
• Obvious duct restrictions, disconnected sections, or leakage observations
• Access limitations that prevented a full test

A simple system summary makes the report easier to review:

Only include fields that your team can test and interpret within the assigned scope. Empty or guessed fields weaken the report.

Show how the readings were obtained

The report should identify the test approach well enough for another qualified reviewer to understand what the number represents. At a minimum, note the instrument type or test method used and any instrument identification your company tracks.

A report field set can include:

• Instrument or method used
• Instrument identifier
• Date checked or calibration status, if your company maintains that information
• Location of each measurement
• Whether the reading was a direct device reading, a duct traverse, a hood reading, or another documented method
• Any factor or conversion used in the calculation

Avoid presenting calculated values as direct measurements. If a total was calculated from several points, label it as a calculation and retain the component readings in the job file.

Track adjustments in the order they were made

Air systems are interdependent. An adjustment at the fan, main duct, branch damper, or terminal can affect other readings. A report should therefore show both the starting condition and final condition, not just a final list of numbers.

A practical adjustment sequence is:

1. Verify the system is operating under the intended test conditions.
2. Address obvious conditions that prevent meaningful testing, such as a blocked return path, damaged duct, heavily loaded filter, or closed damper.
3. Establish the equipment-level airflow condition required for the scope.
4. Adjust main and branch distribution components before fine-tuning terminal devices.
5. Recheck affected areas after material adjustments.
6. Record the final readings and any limits on the result.

The exact procedure depends on the equipment and project scope. The reporting principle remains the same: a reviewer should be able to tell what was changed, why it was changed, and what the final reading was after that change.

Use notes such as:

• “Opened branch damper approximately one-quarter turn; rechecked three downstream supply devices.”
• “Return grille remained partially restricted by built-in cabinetry; customer advised that airflow cannot be fully evaluated until access is cleared.”
• “No terminal adjustment made; final reading recorded for baseline only.”

Avoid vague notes such as “balanced system” without supporting readings or a defined acceptance basis.

Make exceptions visible

A strong air balance report does not hide unresolved items. It separates completed work from limitations, recommended repairs, and items outside the approved scope.

Create an exceptions section for issues such as:

• A reading outside the stated target or project tolerance
• An inaccessible device or area
• Missing design information
• A damaged, disconnected, or restricted duct component
• Controls that prevented the unit from maintaining the intended test condition
• A room condition that could not be evaluated during the visit
• Work that requires authorization, additional access, materials, or a return visit

For each exception, state the issue, likely operational effect if known, recommended action, responsible party if assigned, and whether the final report result is conditional on that item.

This protects the customer from assuming a limitation has been resolved and helps your office estimate follow-up work accurately.

Add a clear final summary

The conclusion should answer the customer’s practical question: what did the team verify, what was adjusted, and what still needs attention?

A concise final summary can cover:

• Systems and areas tested
• Whether readings were recorded before and after adjustment
• Whether the final condition met the identified job target, where a target was available
• Remaining exceptions or access limitations
• Recommended next step and timing, if follow-up is needed

For example:

Airflow was tested at the listed devices for AHU-1. Final readings are shown in the terminal schedule. Two devices could not be tested because access was blocked. The report does not establish final conditions for those locations; return access is required before a complete evaluation can be made.

Keep the conclusion consistent with the data. If the report records observations only, say so. If the work was limited to a specific zone, do not imply that the entire building was balanced.

Use sign-off to close the documentation loop

Sign-off does not need to imply that every party agrees with every technical conclusion. It should document who performed the work, who reviewed the report, and whether the customer received the stated findings.

Include space for:

• Technician or lead tester name and signature
• Date of completion
• Internal reviewer, if your process uses one
• Customer or site representative acknowledgment
• Customer comments or exceptions noted at turnover

Attach supporting material where useful: marked-up floor plans, equipment schedules, photos of access limitations or damaged components, and calculation sheets. Keep those files with the job record.

If you need a customer-facing document for billing or turnover alongside the technical report, use a clear receipt that identifies the work performed and links it to the job record. See Air Conditioner Receipt Template: What to Include for the core details to retain.

Air balance report checklist

Before sending the report, confirm that it includes:

• Customer, site, job, and system identifiers
• Scope of the test and areas included
• Relevant operating conditions at the time of testing
• Target values and the source of those targets, when available
• Measurement method or instrument information
• Before-and-after readings where adjustments were made
• Equipment-level readings or notes needed to interpret terminal results
• Specific adjustment notes
• Final readings with consistent units
• Clearly marked exceptions, limitations, and follow-up work
• Final summary that matches the recorded data
• Technician completion and customer acknowledgment fields
• Supporting schedules, photos, calculations, or marked-up plans when needed

A report built this way is useful beyond the day of service. It provides a defensible record of the conditions tested, gives the customer a clearer explanation of the work, and gives your team a baseline for future troubleshooting or maintenance.