New construction in Florida with the ducts in the attic.

Florida Duct Leakage Test Requirements (New Construction)

Code Reference: Florida Energy Conservation Code (FECC) 2020, based on IECC 2018, Section R403.3.

Requirements:

• Duct leakage testing is mandatory for all new residential construction with ducts in unconditioned spaces (e.g., attics).
• Test Method: Must comply with ACC AAH 1-2014 (or latest ACCA standard).
• Leakage Limit:
• ≤ 6% total leakage (measured at 25 Pa pressure) for ducts outside the conditioned space.
• ≤ 4% total leakage if all supply and return ducts are within the conditioned space (rare in attic installs).

Key Details:

• Test must be performed by a certified technician (BPI, RESNET, or equivalent).
• Documentation required: Test report submitted to code official.
• Exemptions: Ducts entirely in conditioned space (not applicable for attic ducts).

Practical Notes:

• Use mastic or UL 181 tape for sealing joints.
• Ensure proper access for testing (test ports).
• Schedule inspection after testing and before drywall closure.

Bottom Line: For attic ducts in Florida new construction, you must achieve ≤ 6% leakage per ACCA standards. Test and document before final inspection.

If unsure about certification or procedures, consult a licensed HVAC or energy rater.

Florida (2023 FBC-Energy / 2021 IECC with FL amendments):

Test Required: Total Duct Leakage (Rough-in or Post-construction). Code Ref: R403.3.4 (mandatory), R403.3.5 (testing criteria).

The Number: ≤ 4 CFM₂₅ per 100 ft² of Conditioned Floor Area (CFA).

Critical Details for Attic Ducts:

1. Test Method: Use a duct blaster. Pressurize to 25 Pa (0.1 in. w.c.).
2. Rough-in Timing: Test after ducts are installed/sealed but before drywall/insulation covers connections. Register boots taped/grilles sealed. Air handler can be installed (preferred) or taped off.
3. Post-Construction Timing: Test after finish. Register grilles installed (sealed for test). Air handler must be installed.
4. Attic Penalty: None in FL code for total leakage limit (stays 4 CFM₂₅/100ft²). Contrast: IECC base code allows 8 CFM₂₅/100ft² for "Total" if air handler not installed at rough-in; FL Amendment R403.3.5 deletes this exception. You hit 4 CFM₂₅/100ft² regardless of stage.
5. Ducts in Attic = R-8 Insulation Minimum (R403.3.1). Verify insulation before you bury connections.

Pro Tip: With attic ducts, target ≤ 2 CFM₂₅/100ft² at rough-in. Attic connections are hard to fix after spray foam/drywall. Seal every collar, boot-to-drywall, and AHU connection with mastic (UL 181B-M) or approved tape (UL 181B-FX). Don't rely on cloth duct tape.

Verification: Third-party certified tester (RESNET/HERS or FL licensed) required per R403.3.4. Results on Energy Code Certificate (R401.3).