Direct answer
Closed-cell (R-7 per inch) for crawl spaces, rim joists, below-grade, and where vapor barrier matters. Open-cell (R-3.7 per inch) for attics and interior walls where vapor permeability is OK. Both air-seal effectively.
Authoritative sources
- US Department of Energy ↗
DOE Energy Saver guide to insulation types, R-values, and recommended applications.
- IRS Section 25C ↗
Energy Efficient Home Improvement Credit — up to $1,200/yr for qualifying insulation work.
- Energy Star ↗
Energy Star recommendations for attic and wall insulation R-values by climate zone.
Related questions
- How much does spray foam insulation cost in Cincinnati? →
- How does spray foam compare to fiberglass and cellulose? →
- Are there tax credits for spray foam in 2026? →
- How long does spray foam insulation last? →
- How much will I save on heating and cooling? →
- How long does spray foam installation take? →
- Can I be home during the install? →
- Should I foam the roof deck or the attic floor? →
- Will spray foam cause humidity problems in my home? →
Ready to get started in Cincinnati?
We connect Greater Cincinnati homeowners with BPI-credentialed spray foam installers in our partner network. Mon–Fri 7am–6pm · Sat 9am–3pm.