Manual J for the sales phase - when permit-grade isn't required (yet).

No single rule covers every permit. For new construction under an IECC-based residential energy code, §R403.7 of the IECC requires heating and cooling equipment to be sized per ACCA Manual S based on loads calculated with ACCA Manual J or another approved methodology. In the IECC 2015 text that Texas and Georgia build on, the alteration rules for existing buildings (§R503.1.2) do not list §R403.7, so for an equipment replacement in an existing home the load calculation requirement, if any, comes from the AHJ. Whether the AHJ asks to see that calculation with the permit application, and in what format, is a local decision. Check with the local building department before assuming.

It depends on the energy code in force and on the local building department, not just the state. California is the clearest case: Title 24 Part 6 (2025) §150.0(h)1 requires single-family loads to be calculated with the ASHRAE Handbook, SMACNA, or ACCA Manual J. States on an IECC-based code (Texas on IECC 2015 with amendments, Florida on the 2023 Florida Energy Conservation Code based on IECC 2021, Georgia on IECC 2015 with amendments) carry the IECC §R403.7 sizing rule for new construction. Arizona has no statewide residential energy code, so it depends on the city or county. Always verify with the AHJ before submittal.

No. BuildSolver is not ACCA-approved and does not produce a permit submittal. The result PDF states that it is for estimation purposes only. For permit submission, use software on ACCA's list of approved Manual J software, such as Wrightsoft Right-J8 or Cool Calc Manual J.

A sales-phase estimate is a quick load calculation from building-level inputs and defaults, done before you have plans or measurements. A permit submittal is usually a full Manual J with inputs taken from the actual plans or site measurements, often room by room so the duct design can follow, prepared in ACCA-approved software. The procedure is the same; the input detail and the documentation differ.

Texas's residential energy code is the 2015 IECC with amendments, in effect since September 1, 2016 (DOE Building Energy Codes Program). For new construction, §R403.7 of the IECC requires heating and cooling equipment to be sized per ACCA Manual S based on loads calculated with ACCA Manual J or another approved methodology. The IECC 2015 alteration rules for existing buildings (§R503.1.2) do not list §R403.7, so for a change-out the local building department decides. Home-rule cities may adopt a newer edition, so verify with the AHJ.

It requires a load calculation, with Manual J as one of three allowed methods. Title 24 Part 6 (2025 cycle, in effect since January 1, 2026) §150.0(h)1 lists the ASHRAE Handbook, the SMACNA Residential Comfort System Installation Standards Manual, and ACCA Manual J, and §150.0(h)5 requires systems to be sized based on ACCA Manual S-2023. §150.2(b)1C applies the same rules to a complete system replacement, meaning all the heating or cooling equipment plus a new or replacement duct system; for an equipment-only change-out, ask the AHJ. BuildSolver does not produce Title 24 compliance documents.

Software on ACCA's list of approved Manual J software, such as Wrightsoft Right-J8 (Windows) or Cool Calc Manual J (browser). BuildSolver is for the sales phase that comes before any of this - quoting the job, sizing the equipment for the proposal, deciding whether to bid.