Find out how much you'll save with proper attic insulation and how quickly it pays for itself.
Our calculator estimates your insulation savings based on climate, current insulation level, and home size:
This is critical! Air leaks carry 2-5x more heat than conduction through insulation. Seal all attic penetrations (recessed lights, vents, chimneys) with spray foam before adding insulation. Otherwise you're wasting money on insulation that won't work properly.
R-value measures resistance to heat flow. Higher = better. R-38 = 10-13 inches of blown insulation. R-49 = 16-17 inches. Check your attic - if you can see floor joists, you need more insulation.
Blown-in (cellulose or fiberglass) fills gaps better and costs less to install ($1.50-2.00/sq ft). Batts (fiberglass rolls) are DIY-friendly but harder to install properly around obstacles. For attics, blown-in is usually best.
Attics need ventilation to prevent moisture buildup and ice dams. Install baffles (foam or cardboard channels) between rafters before adding insulation. This ensures airflow from soffit vents to ridge vents. Cost: $2-3 per baffle.
DIY batts: $0.50-1.00/sq ft materials only. Takes 1-2 days. Good for small attics. Professional blown-in: $1.50-2.00/sq ft installed. Takes 4-8 hours. Better coverage, equipment rental avoided. Most homeowners choose professional for blown-in.
Depends on climate. Cold climates (Zone 6-7): R-49 to R-60. Moderate climates (Zone 4-5): R-38 to R-49. Hot climates (Zone 1-3): R-30 to R-38. Check Energy Star's recommendations by ZIP code. Most homes built before 2000 need more insulation.
Yes! Just blow new insulation over the old. However, you MUST air seal first. Existing insulation may be hiding air leaks. Have a professional do a blower door test and seal leaks before adding more insulation. Never compress old insulation - this reduces its R-value.
Fiberglass and cellulose insulation lasts 40-80+ years if properly installed and maintained. Cellulose may settle 10-20% over time, reducing R-value slightly. Check every 5-10 years for moisture damage, pest problems, or compression. Well-maintained insulation is essentially permanent.
Both work well. Cellulose (recycled paper) costs slightly less, has better soundproofing, and is more eco-friendly. Fiberglass doesn't settle as much and is fire-resistant. For attics, cellulose is often preferred due to cost ($1.20-1.50/sq ft vs $1.50-2.00). Both achieve similar R-values per inch.
Attic first! Walls account for 20-25% of heat loss vs 25-35% for attics. Wall insulation is expensive ($2-5/sq ft) because you need to drill holes or remove drywall. Only do walls if: (1) attic is already insulated to recommended R-value, (2) you're renovating anyway, or (3) walls have NO insulation (pre-1940 homes).
Yes! Many utilities offer rebates of $0.15-0.30 per square foot. Federal tax credits may apply (check current IRS rules). Some states have additional programs. Low-income homeowners may qualify for FREE weatherization through state programs. Check dsireusa.org for your area's incentives.
See how insulation ranks against air sealing, HVAC upgrades, and 19 other energy improvements.
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