ASHRAE 62.2 sets a minimum continuous ventilation rate for residential indoor air quality. After spray foam tightens the envelope, many Columbus homes drop below the natural-infiltration threshold and need mechanical ventilation (typically an HRV or ERV at $2,500-$5,000) to meet the standard.
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ASHRAE Standard 62.2 (Ventilation and Acceptable Indoor Air Quality in Residential Buildings) is the standard most building codes reference for residential ventilation requirements. The math in plain English: a home needs approximately 7.5 CFM (cubic feet per minute) per occupant of fresh air, plus 0.01 CFM per square foot of conditioned floor area. For a 2,500 sqft Columbus home with 4 occupants: 4 x 7.5 + 0.01 x 2,500 = 30 + 25 = 55 CFM of continuous fresh-air requirement. Pre-foam, most Columbus homes meet this through natural air leakage; an 8 ACH50 home leaks plenty of air to satisfy 62.2 unaided. Post-foam, homes that test 4-5 ACH50 may be below the natural-infiltration threshold and need a mechanical solution. Three equipment options. (1) Heat recovery ventilator (HRV): captures heat from outgoing air and transfers it to incoming fresh air; well-suited to the long cold Columbus heating season but lacks moisture recovery. Cost: $2,000-$3,500 plus install. (2) Energy recovery ventilator (ERV): captures both heat and moisture; often chosen for Columbus because summer humidity loads benefit from the moisture-recovery feature while the core still recovers heat through the winter. Cost: $2,500-$4,500 plus install. (3) Bath-fan-based continuous exhaust with supply-air vents: cheapest option ($500-$1,500) but offers no heat or moisture recovery and is uncommon in Columbus, where the heating penalty of exhausting conditioned air is significant. Most credentialed Columbus foam installers run the 62.2 calculation as part of the post-foam closeout package. If the resulting CFM requirement exceeds the natural-infiltration capacity of the post-foam envelope, the ventilation upgrade is recommended in writing. Homeowners who skip the ventilation step often experience indoor humidity creep over the first winter (stuffier feel, condensation on cold windows, occasional mold on cool exterior wall surfaces). Pairing the ventilation upgrade with the foam install is the cleanest approach, both for cost (one site visit, integrated commissioning) and for indoor air quality continuity.