Spray Foam vs Fiberglass Insulation

Updated March 24, 2026 · Expert-verified answer

Quick Answer

Fiberglass ($0.50–$1.50/sq ft) is budget-friendly and DIY-able. Spray foam ($1.50–$4.50/sq ft) has higher R-value, air-seals, and lasts longer. Spray foam pays for itself in energy savings in 5–7 years.

Cost Breakdown

Service Low High Notes
Fiberglass batts (per sq ft) $0.50 $1.50
Blown-in cellulose (per sq ft) $0.75 $2.00
Open-cell spray foam (per sq ft) $1.00 $2.50
Closed-cell spray foam (per sq ft) $2.00 $4.50
Attic insulation (full) $1,500 $4,000

Spray Foam vs Fiberglass Insulation

Fiberglass ($0.50–$1.50/sq ft) is budget-friendly and DIY-able. Spray foam ($1.50–$4.50/sq ft) has higher R-value, air-seals, and lasts longer. Spray foam pays for itself in energy savings in 5–7 years.

Related Questions

How do I find a good insulation installation professional?

Check reviews, verify licensing and insurance, get 2-3 quotes, and ask for references from recent projects.

Do I need a permit for insulation installation?

It depends on the scope. Most cosmetic work doesn't need permits, but structural, electrical, and plumbing changes typically do. Your contractor should know local requirements.

How can I save money on insulation installation?

Get multiple quotes, schedule during off-peak seasons, bundle multiple projects, and ask about payment discounts.