Spray Foam vs Blown-In vs Fiberglass Insulation
The short answer
Fiberglass batts and blown-in insulation cost less per square foot. Spray foam costs more but also seals air leaks in the same step. In a humid state like Arkansas, the right choice depends on where the insulation goes and whether air leaks are the real problem. Blown-in or batts plus careful air sealing can be a good value; spray foam often makes sense on roof decks, rim joists, metal buildings and crawl space walls.
On this page
Cost compared (national averages)
| Insulation type | Installed cost per sq ft | Source |
|---|---|---|
| Fiberglass batts and rolls | $0.80–$2.60 | HomeGuide, Dec 2025 |
| Blown-in (fiberglass or cellulose) | $1.00–$2.80 | HomeGuide, Nov 2025 |
| Spray foam | $1.00–$4.50 | HomeGuide, Dec 2025 |
| Open-cell spray foam | $1.50–$3.50 | HomeGuide, Dec 2025 |
| Closed-cell spray foam | $3.00–$5.00 | HomeGuide, Dec 2025 |
National averages, not quotes. The two HomeGuide spray foam pages use different samples, so their ranges differ. Arkansas prices vary — get a free written estimate from a partner contractor.
Air sealing: the biggest difference
Batts and blown-in slow heat flow but let air pass through gaps unless the gaps are sealed first. Spray foam fills gaps as it is applied. ENERGY STAR estimates an average 15% saving on heating and cooling costs from air sealing plus insulation (ENERGY STAR) — an average, not a promise. Learn how foam types differ in open-cell vs closed-cell and in the DOE overview of insulation types.
Which fits where
| Location | Often a good fit | Why |
|---|---|---|
| Vented attic floor | Blown-in | Low cost per square foot; air seal the attic floor first |
| Roof deck / unvented attic | Spray foam | Brings ducts in the attic inside the insulated space |
| Open wall cavities | Batts or spray foam | Batts cost less; foam also air seals |
| Rim joists | Spray foam | Hard to seal with batts |
| Metal buildings and barndominiums | Closed-cell spray foam | Also a vapor barrier against condensation |
| Crawl space walls | Closed-cell spray foam or encapsulation | Moisture control in humid air |
R-value per inch
| Material | R-value per inch | Source |
|---|---|---|
| Blown-in fiberglass | 2.2–2.9 | HomeGuide, Nov 2025 |
| Blown-in cellulose | 3.1–3.8 | HomeGuide, Nov 2025 |
| Open-cell spray foam | 3.5–3.7 | HomeGuide, Dec 2025 |
| Closed-cell spray foam | 5–7 | HomeGuide, Dec 2025 |
R-value measures resistance to heat flow. It does not measure air leakage, which is why an air-sealed attic with blown-in can outperform a leaky one with more R-value.
Moisture in humid Arkansas
Most of Arkansas is in IECC climate zone 3A, the warm and humid zone (PNNL climate zone guide). Humid air moving through gaps can condense on cool surfaces. Closed-cell foam also acts as a vapor barrier, which is why it is common on metal buildings and crawl space walls; blown-in and batts need a separate air and vapor plan. See crawl space encapsulation.
Combining materials
Many homes use more than one material: closed-cell foam on rim joists, blown-in on a vented attic floor after air sealing, and batts in open interior walls. Ask a partner contractor to explain the plan for each area and price each part separately.
DIY or professional?
Batts and some blown-in jobs are common DIY projects. Spray foam needs protective equipment, proper mixing temperatures and ventilation, so most homeowners hire it out. Small DIY foam kits suit gaps and penetrations, not whole attics.
How much can you save? EPA’s ENERGY STAR methodology estimates that air sealing plus insulation cuts heating and cooling costs by an average of 15% nationally, and 14% in climate zone 3 (ENERGY STAR). Those are averages for a typical older house, not a promise; a leaky attic has more to gain than a newer, tighter home.
How to compare spray foam quotes
- Foam type (open-cell or closed-cell) for each area.
- Finished thickness in inches and the R-value it gives.
- Square footage of surface sprayed, not just floor area.
- Prep and removal of old insulation as a separate line.
- Ignition or thermal barrier coating where code requires it.
- Ventilation and re-entry time after spraying.
Many spray foam companies have a minimum job fee of $1,000–$2,000 or more (HomeGuide, Dec 2025), so very small jobs can cost more per square foot. If two quotes for the same space are far apart, the difference is usually thickness or scope.
Safety and curing
Spray foam is applied as a liquid that reacts and cures, so occupants usually stay out during spraying and ventilation. Ask the contractor for the re-entry time for the product they use. Read spray foam off-gassing, is spray foam safe and the DOE overview of insulation types.
How the free estimate works
- Send your request through the estimate form.
- Foam Masters ARK passes it to an independent partner contractor who serves your area.
- The contractor contacts you to look at the space and prepare a written estimate.
- You compare it and decide. There is no obligation.
Pros and cons
- Fiberglass batts: lowest cost, easy to find; gaps and compression reduce performance.
- Blown-in: fills irregular attic floors well; settles over time and does not air seal by itself.
- Spray foam: insulates and air seals in one step; costs more, needs trained installers and proper cure time (see spray foam off-gassing).
Frequently asked questions
Get a free estimate for your home property
Foam Masters ARK is a referral service, not the installer. Tell us about your project and we pass it to an independent partner spray foam contractor who serves your area for a free written estimate. Before you hire, ask for the foam type, the finished thickness in inches and the square footage on the quote, and ask the contractor for their own documentation. See questions to ask a spray foam contractor.