How Much Does Insulation Cost? Attic, Wall, and Basement Guide
Insulation is the highest-ROI home improvement for energy savings. Here is what it costs and what it saves.
Attic insulation (most common and highest impact): blown-in fiberglass or cellulose $1.50-3.00 per square foot installed. A 1,000 sq ft attic: $1,500-3,000. Wall insulation (retrofit): blown-in $2-4 per square foot. Basement/crawl space: spray foam $3-7 per square foot, fiberglass batts $1-2 per square foot.
What You Actually Save
Properly insulating an under-insulated home saves 15-30% on heating and cooling costs — $200-600/year for the average home. Attic insulation has the highest ROI because hot air rises — an under-insulated attic loses 25-30% of heating energy. The payback period for attic insulation is typically 2-4 years, making it one of the fastest-returning home investments available.
R-Value Guide
R-value measures thermal resistance — higher is better. Recommended attic insulation by climate zone: Zone 1-3 (South): R-30 to R-38. Zone 4-5 (Mid-Atlantic, Midwest): R-38 to R-49. Zone 6-7 (North): R-49 to R-60. Each inch of fiberglass adds about R-3.2. Each inch of spray foam adds R-6 to R-7. If your attic has less than 10 inches of insulation, adding more is almost certainly cost-effective.