Insulation Calculator

Calculate insulation needs for attics, walls, crawlspaces, and floors. Compare 8 insulation types by R-value, cost, and coverage. Includes climate zone recommendations, DIY vs professional costs, and energy savings payback estimates.

Share
Thickness
10.9"
inches needed
Units
88
bag(s)
DIY Cost
$1,596
materials only
Annual Savings
$18
payback: 89.4 yrs
Cost Breakdown
ItemCost
Blown-In Cellulose (88 bags)$1,596
Professional Labor$960
DIY Total$1,596
Professional Total$2,556
Insulation Type Comparison
TypeR/Inch$/sqft/RNotes
Fiberglass Batts3.2$0.05Most common, DIY-friendly
Blown-In Fiberglass2.5$0.04Great for attics, fills gaps
Blown-In CelluloseSelected3.5$0.035Eco-friendly, good coverage
Spray Foam (Open Cell)3.7$0.08Air sealing + insulation
Spray Foam (Closed Cell)6.5$0.12Highest R-value, moisture barrier
Rigid Foam Board (XPS)5.0$0.07Great for basements, foundations
Rigid Foam Board (Polyiso)6.0$0.09Best R-value per inch, foil-faced
Mineral Wool Batts3.3$0.07Fire resistant, soundproofing
Recommended R-Values by Climate Zone
Zone 1 (Hot-Humid)
Attic:R-30
Wall:R-13
Floor:R-13
Zone 2 (Hot-Humid)
Attic:R-38
Wall:R-13
Floor:R-13
Zone 3 (Warm)
Attic:R-38
Wall:R-20
Floor:R-25
Zone 4 (Mixed)
Attic:R-49
Wall:R-20
Floor:R-25
Zone 5 (Cool)
Attic:R-49
Wall:R-20
Floor:R-30
Zone 6 (Cold)
Attic:R-49
Wall:R-21
Floor:R-30
Zone 7-8 (Very Cold)
Attic:R-60
Wall:R-21
Floor:R-38

How to Use Insulation Calculator

  1. 1Select area type and dimensions
  2. 2Choose insulation type
  3. 3Set target R-value for your climate zone
  4. 4View materials needed and cost estimate

Frequently Asked Questions

How much insulation do I need?

It depends on your climate zone and area being insulated. Most attics need R-38 to R-60, walls need R-13 to R-21, and floors need R-25 to R-30. The DOE provides recommended R-values for 8 US climate zones.

Which insulation type is best?

Fiberglass batts are cheapest and DIY-friendly. Blown-in cellulose fills gaps well for attics. Spray foam provides the best air sealing. Choose based on your budget, application area, and whether you're DIY or hiring a professional.

How much does insulation cost?

Fiberglass batts: $0.50-1.00/sqft at R-13. Blown-in cellulose: $0.80-1.50/sqft at R-38. Spray foam: $1.50-4.00/sqft. Professional installation adds 50-100% to material costs. Attic insulation typically pays back in 3-7 years through energy savings.

About Insulation Calculator

Calculate insulation needs for attics, walls, crawlspaces, and floors. Compare 8 insulation types by R-value, cost, and coverage. Includes climate zone recommendations, DIY vs professional costs, and energy savings payback estimates.

NexTool's Insulation Calculator is completely free to use with no sign-up required. Your data is processed directly in your browser and never sent to our servers, ensuring complete privacy and instant results.

Stay Updated

Get notified about new tools, features, and exclusive deals. No spam, ever.