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Insulation R-Value Calculator

Climate zone + application → DOE target R-value and inches of insulation needed.

Where this fits

📦 Business & Seller OpsGoing 1099FreelancersFounders

This tool lives inside Going 1099 and is most useful for freelancers and founders.

Corp Tax Rate21%
SE Threshold$400
FICA Cap 2024$168,600

Location & Application

Assessment

You need R-30 more. Add 8.1 inches of Blown Cellulose.

DOE target
R-49
attic, zone 5
Existing
R-19
current insulation
Inches needed
8.1 in
Blown Cellulose
Bags (blown)
~244
estimate only
1

DOE target R-value

Lookup: DOE Table by climate zone + application

= R-49

Zone 5 (cool), application: attic

2

Additional R needed

additionalR = max(0, target − existing)

= max(0, 49 − 19)

= R-30 more needed

3

Inches of insulation required

inches = additionalR ÷ R-per-inch

= 30 ÷ 3.7

= 8.1 inches of Blown Cellulose

Blown Cellulose = R-3.7/inch

Key insight

R-values are additive — existing batts plus new blown-in layers stack. Closed-cell spray foam also acts as an air barrier, which can be worth more than the R-value alone in leaky older construction.

Use this result in →

🌡️HVAC BTU Sizing🪟Drywall Sheet Calculator

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