What HECS documents on residential ventilation projects in 2026.

Why Kentucky's Tight Envelopes Are a Ventilation Problem

Kentucky homes in 2026 routinely test at 2.0-3.0 ACH50. Louisville (Jefferson County) sits in climate zone 4A under the 2024 IECC Climate Zone Map (DOE Building America), and the rest of the state ranges from CZ 4A to CZ 5A. With that level of envelope tightness, natural infiltration alone cannot satisfy ASHRAE 62.2-2022 §4.1, which requires a whole-building mechanical ventilation rate calculated as Q_total = 0.03·A_floor + 7.5·(N_br+1) cfm.

In our 2026 sample of residential projects across Kentucky, Indiana, and Ohio, the most frequent field finding is that the builder installed a bath fan and assumed it counted as whole-building ventilation. It does not. A 50 cfm intermittent bath fan cannot substitute for a properly sized HRV/ERV running continuously at the calculated rate. Without mechanical ventilation sized to §4.1, the home depressurizes, pulls unconditioned air through every penetration, and the homeowner ends up with humidity spikes, CO₂ readings above 1,000 ppm, and formaldehyde off-gassing that ASHRAE 62.2-2022 is specifically written to mitigate.

The second most common finding: duct leakage. When ducts run through vented attics, still standard practice in Kentucky production housing, total leakage to outside must be verified ≤ 4 CFM25 per 100 ft² conditioned floor area per 2024 IECC R403.3.5. HECS rough-in tests in 2025-2026 routinely show 6-10 CFM25 per 100 ft² before sealing, well above the limit and a direct driver of depressurization that confounds ASHRAE 62.2-2022 compliance.

The Code Requirements in Plain English

ASHRAE 62.2-2022 establishes three distinct compliance obligations for residential buildings:

• Whole-building ventilation per §4.1, mechanical supply or balanced system sized by the equation above.
• Local exhaust per §4.3, kitchen range hoods (≥100 cfm intermittent or ≥25 cfm continuous), bathrooms (≥50 cfm intermittent).
• Filtration credit per §4.1.4, MERV-rated HVAC equipment can reduce required mechanical ventilation rate (updated by Addendum a, February 2024).

These are not alternatives. A home passing §4.1 but failing §4.3 kitchen exhaust is non-compliant. The 2024 IECC makes the same point indirectly, Table R402.4.1.1 caps CZ 4A and CZ 5A (all of Kentucky) at 3.0 ACH50, which is tight enough that the §4.4 infiltration credit is typically meaningless. Per §4.4, the credit is capped at the lesser of 2 ACH50 or a small floor-area term, and a 3.0 ACH50 home gets no credit at all.

For NGBS-2023 certified projects, ICC 700-2023 §903 explicitly cites ASHRAE 62.2-2022 as the indoor environmental quality reference. For projects also pursuing ENERGY STAR MFNC v1.3 (Rev05) National, the ENERGY STAR Multifamily New Construction Functional Testing Checklist Verifier must sign off on HVAC and ventilation performance. The two certifications stack, passing one does not waive the other.

How HECS Documents Compliance

HECS performs ASHRAE 62.2-2022 verification as part of our indoor-air-quality scope, typically alongside blower door and duct leakage testing. The workflow:

1. Pre-test plan review. HECS reviews the mechanical schedule, the §4.1 calculated ventilation rate (builder's worksheet or HECS calculation), and the duct design. We flag missing kitchen exhaust or undersized HRV/ERV before mobilization.
2. Blower door test. ASTM E779 single-point or multi-point, typically run before and after any remediation. We test against the 2024 IECC R402.4.1.2 threshold of 3.0 ACH50 for Kentucky's CZ 4A/5A.
3. Duct leakage test. Total leakage to outside at rough-in (mastic not yet cured) and post-construction, per RESNET/ICC Standard 380 and §R403.3.5.
4. Flow verification. HECS uses a powered flow hood or Duct Blaster to verify bath fan, kitchen hood, and HRV/ERV airflow against §4.3 and §4.1 design values. We do not assume nameplate cfm is actual cfm.
5. Report. A single compliance package documenting all three ASHRAE 62.2-2022 obligations, with field-measured numbers and pass/fail callouts.

The HECS indoor-air-quality services page lists this scope explicitly. For projects also pursuing FORTIFIED Home certification under the 2025 FORTIFIED Home Standard (effective 2025-11-01), the same IAQ testing rolls into the third-party evaluator deliverable.

What HECS Verifies and What Shows Up in the Report

The HECS ASHRAE 62.2-2022 compliance report is built around pass/fail documentation a code official, lender, or program administrator can accept on first read. The deliverable includes:

• Calculated required ventilation rate from §4.1 with the actual floor area and bedroom count used.
• Measured blower door result in ACH50 and CFM50, with the 2024 IECC threshold applied.
• Measured duct leakage to outside in CFM25 per 100 ft² conditioned floor area, against the R403.3.5 / R402.4.2 limit.
• Measured airflow (cfm) at every local exhaust device, kitchen hood and each bath fan, against §4.3.
• Measured whole-building ventilation airflow, against the §4.1 calculated value.
• MERV rating of installed filter, with the §4.1.4 credit applied if applicable (Addendum a, February 2024).
• Photo log of each terminal device, equipment nameplate, and the air handler configuration.

What HECS finds repeatedly in 2026 projects:

Frequently Asked Questions

Does ASHRAE 62.2-2022 apply to single-family detached homes in Kentucky, or only multifamily?

ASHRAE 62.2-2022 applies to all residential buildings, single-family, multifamily, low-rise, townhouses. Kentucky has not adopted ASHRAE 62.2 directly, but NGBS-2023 §903 cites it, ENERGY STAR MFNC requires it, and any HERS Rater compliance path under the 2024 IECC R405 simulated performance alternative effectively requires it. Builders working with HECS on third-party certification should assume it applies.

If the home passes a blower door test at 3.0 ACH50, does it satisfy ASHRAE 62.2-2022?

No. A 3.0 ACH50 result meets the 2024 IECC R402.4.1.2 envelope tightness limit, but per ASHRAE 62.2-2022 §4.1 it triggers the requirement for mechanical ventilation sized to the equation. A tight home without mechanical ventilation is a ventilation failure. HECS documents both the envelope result and the mechanical ventilation measurement in the same report.

Can HECS verify ASHRAE 62.2-2022 compliance on a home that has already been built, or only on new construction?

Both. For existing homes, HECS performs diagnostic testing, blower door, duct leakage, and spot airflow measurements, and produces a remediation list keyed to §4.1, §4.3, and §4.1.4. For new construction, the same testing fits inside