Manual J, S, and D Documentation: What to Keep for Permits and Inspections

Keep the final versions of the applicable design reports prepared for the project: the Manual J load calculation, the Manual S equipment selection report, and the Manual D duct design if one was prepared. Not every project necessarily has all three reports; Manual D may not apply to a fully ductless system. These are the documents that support the permit application and describe the intended system.

Final design reports document the intended design and any design revisions. They do not independently verify the equipment, ductwork, or performance actually installed. If any reports were revised during the project, keep the final revised versions along with superseded versions when needed to understand the revision history. If the installed system differs from the design, retain separately documented as-installed information and any required approved revisions.

Keep a record of the specific equipment models installed. Model information may include the outdoor unit, indoor equipment, furnace, coil, air handler, heat kit, and other relevant components as applicable to the system. Include model numbers and serial numbers where available. The installing contractor should verify the actual installed models, approved combinations, compatibility, and manufacturer installation requirements. Savoy Engineering Group provides HVAC design documentation; it does not install equipment or verify as-installed model numbers.

Retain manufacturer expanded performance data when it was used in the Manual S analysis or is otherwise available. Not every equipment category has identical expanded performance tables, and such data is not always provided directly to the homeowner. Manual S equipment selection relies on applicable sizing criteria and appropriate equipment-specific performance information at relevant design conditions. Manufacturer-rated performance information used for design is distinct from measured performance of the installed system.

If a Manual D duct design was prepared, keep the duct drawings or layout documentation that shows the supply and return duct sizes, routing, and register locations. A Manual D report documents the proposed design; it is not proof of installed airflow or static pressure. Manual D may not apply to a fully ductless system.

If the duct system was modified during installation, retain available as-built drawings, contractor notes, or photographs showing the actual changes. If balancing reports, measured airflow, or static-pressure test results were prepared, retain them separately from the design documentation. Not all residential projects produce formal commissioning or balancing documentation.

Keep copies of any permit revisions that were approved during the project. Not every equipment or duct change automatically requires a permit revision; the AHJ determines which changes require revised submissions or approvals. If a revision was required and approved, the approved revision documents the permitted change.

Also keep copies of permit correspondence: the permit application, the permit approval, any plan review comments, and the final inspection record where available. Permit procedures and document availability vary by jurisdiction. A permit approval or final inspection record does not independently prove that the installed system meets every design assumption or performance target; permit records are distinct from installation verification and performance testing.

Keep a record of the outdoor design conditions and other local design criteria used in the Manual J calculation. Manual J weather inputs may include cooling design dry-bulb temperature, coincident wet-bulb or humidity information, heating design temperature, and other applicable data. The HVAC designer normally determines appropriate design conditions using accepted weather data and applicable ACCA methodology, subject to adopted codes and any AHJ-specific criteria. If the calculation is ever reviewed or updated, knowing the original design conditions allows the reviewer to compare results on a consistent basis.

Not every jurisdiction publishes separate design temperatures or mandates a unique weather station. Retain any documented AHJ-specific criteria when applicable.

Keep applicable installation-related documents that may be relevant to future service or renovation: the contractor's warranty, the manufacturer's equipment warranty, and any startup, commissioning, or balancing records when available. Not every project produces a formal startup, commissioning, or balancing report. Retain applicable equipment installation manuals, service records, and maintenance documentation where available.

Installation and field-performance records are separate from Manual J, S, and D design reports. The installing contractor is responsible for installation and applicable manufacturer requirements. Savoy Engineering Group provides residential HVAC design documentation; it does not perform installation, field testing, or code inspections.