Mechanical ventilation, local exhaust, and filtration credits on residential projects in KY, OH, and IN.
ASHRAE 62.2-2022 — Ventilation and Acceptable Indoor Air Quality in Residential Buildings — governs whole-building mechanical ventilation, local exhaust, and air leakage on dwelling units across Kentucky's code-adopted jurisdictions. Louisville Metro and Lexington-Fayette have adopted the 2024 IRC with local amendments that reference 62.2 for ventilation compliance. Indiana and Ohio multifamily projects pursuing NGBS-2023 or ENERGY STAR v3.2 also cite 62.2 as the underlying ventilation standard.
§6.5 (whole-building mechanical ventilation) and §6.4 (in-unit air movement) define the calculation framework. §7.1 (kitchen exhaust) sets a minimum 100 CFM intermittent or 30 CFM continuous requirement. §7.2 (bath and toilet room exhaust) sets a minimum 50 CFM intermittent or 20 CFM continuous requirement. Builders who miss these baselines during design pay for them at rough-in inspection.
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Call (859) 983-7382 Get a Quote§6.5 requires the ventilation rate be calculated per Equation 6.5a for total airflow, balanced to within 10% of design. For a 1,400 ft² three-bedroom unit with four occupants, the calculated rate is typically 60-75 CFM depending on floor area and bedroom count. HECS measures the running fan's delivered airflow with a flow plate or capture hood per AABC or NEBB procedures.
§6.4 requires that air movement between rooms be sufficient to distribute ventilation air. The prescriptive path is a 1 in² per CFM transfer grille or 1 ft² per 100 CFM undercut. HECS documents grille sizing during the rough-in walk-through.
§7.1 requires kitchen range hoods or exhaust fans rated at 100 CFM intermittent / 30 CFM continuous. §7.2 requires bathroom and toilet room exhaust at 50 CFM intermittent / 20 CFM continuous. HECS verifies fan ratings against manufacturer data and confirms duct routing terminates outside the building envelope.
ASHRAE 62.2-2022 normative text does not broadly endorse a MERV-based reduction to the §6.5 ventilation rate. Historical Addendum b addressed filtration credits, but the published 62.2-2022 body uses a performance-based framework. Some AHJs accept credit via performance path when a MERV 13 or better filter is installed, but HECS confirms the AHJ's interpretation before submitting documentation. Based on HECS project data, projects that attempt MERV 13 substitution without AHJ pre-approval fail first review roughly half the time.
HECS performs ASHRAE 62.2-2022 verification, blower door testing, and duct leakage testing for multifamily projects across Kentucky, Indiana, and Ohio. We coordinate the §6.5 airflow measurement with the ENERGY STAR or NGBS rater of record. For a scope call: (859) 983-7382 or hecsusa.com/contact/.
| Compliance Path | Reference | Ventilation Rate Method | Exhaust Verification | Typical Field Result |
|---|---|---|---|---|
| Prescriptive | §6.5 + §7.1 + §7.2 | Equation 6.5a calculation | Fan nameplate + duct routing | Pass rate ~85% based on HECS project data |
| Performance | §6.5 performance alternative | Measured airflow at fan | Capture hood measurement | Pass rate ~90% based on HECS project data |
| ENERGY STAR v3.2 | Aligns with 62.2 §6.5 | Same as prescriptive | Same + HVAC check | Documentation gap most common failure |
| NGBS-2023 | References 62.2 | Same as prescriptive | Same | Filter rating mismatch frequent issue |
The most common failure point across all four paths is documentation — fan curves, duct lengths, and grille sizes appear on the design but not on site. HECS catches this at rough-in verification, before drywall closes the gap.
Duct routing that terminates in the attic instead of the exterior fails §7.1 and §7.2. Inline fans installed without backdraft dampers fail §6.5 pressure balancing. Transfer grilles sized for return air rather than supply compromise §6.4 distribution. HECS flags each during pre-cover and pre-drywall inspections.
ASHRAE 62.2-2022 cross-references ASHRAE 111 for testing procedures. Energy recovery ventilators (ERVs) may reduce §6.5 required airflow by up to 40% per the standard's recovery credit provisions, but the ERV must be rated per AHRI 1060 and the credit must be documented in the compliance submittal.
Does ASHRAE 62.2-2022 require a MERV 13 filter on every multifamily unit? No. §6.5 does not mandate a specific filter MERV rating. ASHRAE 62.2-2022 addresses filtration in its informative appendix material rather than as a normative requirement. Some AHJs grant performance-path credit when MERV 13 or better is installed; confirm with the local code official before claiming the credit.
What is the minimum exhaust rate for a kitchen range hood per §7.1? §7.1 requires 100 CFM intermittent or 30 CFM continuous. HECS verifies the installed fan's rated airflow against the manufacturer spec sheet and confirms duct routing to the exterior.
Can HECS coordinate 62.2 verification with our ENERGY STAR or NGBS rater? Yes. HECS performs the §6.5 airflow measurement, §7.1 and §7.2 exhaust verification, and provides a compliance report formatted for the rater of record. This is standard scope on HECS multifamily projects. See the full 45L Tax Credit Louisville KY workflow at hecsusa.com/45l-tax-credit-louisville-ky/.
HECS delivers ASHRAE 62.2-2022 verification, blower door testing, duct leakage testing, and ENERGY STAR Multifamily Reviewer services across Kentucky, Indiana, Ohio, Tennessee, Illinois, and Missouri. Project scopes range from single-unit INF certification to 200+ unit NGBS-2023 compliance programs. HECS also serves Louisville KY, Lexington KY, Cincinnati OH, Indianapolis IN, Nashville TN, and Evansville IN directly. Reach the team at (859) 983-7382 or [email protected]. Full service list at hecsusa.com/services/; new project intake at hecsusa.com/contact/.
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