Insulation Calculator
Calculate insulation materials for walls, attics, and floors. Estimate R-value requirements, material quantities, and costs for energy-efficient insulation.
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How to Use This Calculator
Calculate insulation needs for walls, attics, and floors to improve energy efficiency:
- Measure the area to be insulated in square feet.
- Select the type of insulation (batts, blown-in, spray foam).
- Choose the R-value needed for your climate zone and application.
- Click 'Calculate' to see materials needed and estimated costs.
Why This Matters
Proper insulation is one of the best investments for home energy efficiency. The Department of Energy estimates that 25-30% of heating and cooling energy is lost through poorly insulated areas. Different climate zones require different R-values, and different applications (walls vs attic) have different requirements. Getting insulation right reduces energy bills for decades while improving comfort year-round.
- Reduce heating and cooling costs significantly
- Improve home comfort by eliminating drafts and hot spots
- Meet building code requirements for your climate zone
- Compare costs between different insulation types
- Calculate coverage accounting for framing and obstacles
Worked Examples
Attic Insulation
Adding insulation to 1,200 sq ft attic in Climate Zone 4 (needs R-49).
Wall Insulation
Insulating 800 sq ft of 2×4 exterior walls with fiberglass batts (R-13).
Crawl Space
500 sq ft crawl space floor, spray foam for moisture barrier and R-19.
Common Mistakes to Avoid
- Using wall R-values for attic applications - attics need much higher R-values.
- Compressing batts to fit - compressed insulation loses R-value significantly.
- Not accounting for framing - studs and joists reduce effective insulating area by 15-20%.
- Ignoring vapor barriers - wrong placement can cause moisture problems.
- Adding insulation without air sealing - air leaks bypass insulation entirely.