A Dublin whole-home foam package with energy-recovery ventilator pairing

The starting point

A 2007 home in Dublin, 2,950 sqft, full unfinished basement, attached two-car garage. Built with code-minimum fiberglass batts in walls (R-13), R-38 attic, R-19 in the floor over the unfinished basement. Pre-foam blower-door test: 7.8 ACH50, typical for code-minimum 2007 construction.

The owners wanted a whole-home foam upgrade as a comfort + utility-cost improvement. They were not in a hurry; they wanted the work scoped properly and were open to multi-day install.

Why ventilation pairing matters at this tightness target

Whole-home foam packages routinely bring blower-door measurements down to 3-5 ACH50, which is excellent for thermal performance but borderline for natural ventilation. ASHRAE 62.2 recommends 0.35 air changes per hour minimum continuous fresh-air ventilation for indoor air quality. At 3-5 ACH50, the natural infiltration during normal weather averages around 0.15-0.30 ACH continuous, below the IAQ minimum.

Without mechanical ventilation, tight homes show predictable problems:

• Elevated indoor humidity (cooking, showering, breathing accumulate moisture)
• Stale-air sensation in winter (when occupants close windows for weeks, a long stretch in Columbus Zone 5A)
• Elevated CO2 in occupied rooms (particularly bedrooms overnight)
• Persistent cooking odors that take longer to clear
• Potential mold growth on cool surfaces
• For homes with natural-draft gas furnaces or water heaters: back-drafting risk on a depressurized envelope (the combustion appliance pulls air down its own flue, spilling combustion gases into the home). Tight homes with combustion appliances should pair the foam install with a combustion-safety test and a radon retest within 90 days because both checks measure the same air-pressure dynamics from different angles.

The fix: an energy-recovery ventilator (ERV) sized to the home, providing controlled fresh-air introduction with energy recovery from the exhaust air. Columbus climate often favors an ERV for the summer humidity benefit while the core still recovers heat through the long winter heating season.

The combined quote

| Foam scope | Cost | |---|---| | Closed-cell rim joist (3 inches) | $2,400 | | Closed-cell at attic roof deck (7 inches, Zone 5A R-49) | $7,800 | | Wall cavity drill-and-fill closed-cell | $5,800 | | Closed-cell at unfinished basement walls | $2,800 | | Pre/post blower-door tests | $400 | | Closeout package (R-value cert, product data, ICC-ES) | $200 | | Foam subtotal | $19,400 |

| ERV scope | Cost | |---|---| | Panasonic FV-04VE1 ERV (rated 60 CFM continuous) | $1,200 | | Ductwork, dampers, controllers | $1,400 | | Installation labor (1 day) | $850 | | Wall-mounted controller + balancing | $250 | | ERV subtotal | $3,700 |

Combined total: $23,100 fixed.

Install timeline (6 days)

• Days 1-2: Foam install (rim joist + basement walls Day 1, attic roof deck Day 2)
• Day 3: Wall drill-and-fill begins
• Day 4: Wall drill-and-fill complete + patch + paint
• Day 5: Blower-door post-test (4.4 ACH50, down from 7.8) + ERV install
• Day 6: ERV balancing + verification

The 12-month follow-up

| Metric | Pre-install | Post-install | |---|---|---| | ACH50 (blower door) | 7.8 | 4.4 | | Indoor RH winter average | 22% (too dry) | 38% (comfortable) | | Indoor RH summer average | 62% (humid) | 50% (comfortable) | | Annual heating cost (Nov-Mar) | $1,680 | $1,000 (-40%) | | Annual cooling cost (Apr-Oct) | $860 | $600 (-30%) | | Total annual utility savings | n/a | $940/year |

The 30-40% utility cost reduction is at the upper end of typical Dublin post-foam outcomes, and the heating-side reduction carries most of the savings given the Zone 5A climate. The humidity stabilization (winter dryness fixed; summer humidity manageable without running AC continuously) was the most-valued non-financial benefit reported.

What this case shows for whole-home foam upgraders

If you are scoping a whole-home foam package on a 2000-2010 Dublin, Powell, New Albany, or Lewis Center home, plan for the ERV/HRV pairing:

1. If the post-install blower-door test will land at 4.5 ACH50 or below, plan for ventilation upgrade. 2. If the post-install ACH50 will land between 4.5-6.0, ventilation upgrade is borderline. 3. If the post-install ACH50 will be above 6.0, ventilation upgrade is generally not required.

Bundle the ERV with the foam at quote time. It adds $2,800-$5,500 to the total but avoids retrofitting later when air-quality concerns surface.