Insulation Calculator - Check Your R-Value & Energy Efficiency

Calculate your current insulation R-value and determine if it meets energy efficiency standards for your climate zone. Our free insulation calculator helps you assess thermal performance and plan upgrades for better energy savings.

How to Use the Insulation Calculator

Measure your wall: Enter the wall length and height in feet. Focus on exterior walls for the most accurate assessment.
Select insulation type: Choose the type of insulation you have or plan to install. Each type has different R-values per inch.
Enter current thickness: Measure or estimate the current insulation thickness in inches.
Choose climate zone: Select your climate zone to get the appropriate R-value target based on building codes.

Pro tip: For best results, measure insulation thickness in multiple locations and use the average. Attic insulation is often the most important for energy savings.

Understanding R-Values & Thermal Resistance

R-value measures thermal resistance - how well insulation prevents heat transfer. Higher R-values mean better insulation performance. The R-value of your insulation depends on both the material type and thickness.

How R-Value Works

R-value is calculated by multiplying the insulation's R-value per inch by its thickness. For example, R-13 fiberglass batts that are 3.5 inches thick provide R-13 thermal resistance.

Climate Zone Requirements

Building codes specify minimum R-values based on climate zones defined by the International Energy Conservation Code (IECC):

Zone 1-2 (Hot climates): R-13 walls (focus on cooling efficiency)
Zone 3 (Mixed): R-13 walls (balanced heating/cooling)
Zone 4 (Cold): R-15 walls (emphasis on heating efficiency)
Zone 5 (Very cold): R-20 walls (extreme cold protection)
Zone 6-8 (Extreme): R-25 walls (arctic conditions)

Energy Savings: Proper insulation can reduce heating and cooling costs by 20-50%. Every inch of additional insulation typically saves 5-10% on energy bills.

Common Insulation Types

Different insulation materials offer different R-values and installation methods:

Fiberglass: R-2.9 to R-4.3 per inch, affordable, common in batts and loose fill
Cellulose: R-3.6 to R-3.8 per inch, eco-friendly, good for existing walls
Spray foam: R-4.6 to R-6.0 per inch, excellent air sealing, professional installation
Rock wool: R-3.6 to R-4.3 per inch, moisture resistant, good soundproofing

Insulation Installation Methods

Batt Insulation (Blanket)

• Pre-cut fiberglass or rock wool panels
• Fits between wall studs (16" or 24" OC)
• DIY-friendly for accessible areas
• Face stapling or friction fit installation
• Best for: New construction, unfinished basements

Blown-In Insulation

• Loose fill fiberglass or cellulose
• Blown into wall cavities or attics
• Requires professional equipment
• Excellent for existing walls
• Best for: Retrofit installations

Spray Foam Insulation

• Expanding foam sprayed into place
• Creates air-tight seal
• Professional installation required
• High R-value per inch
• Best for: Air sealing, irregular spaces

Rigid Foam Boards

• Rigid panels of foam insulation
• Installed on exterior or interior surfaces
• Continuous insulation layer
• Moisture resistant options available
• Best for: Exterior wall sheathing

Energy Efficiency Benefits of Proper Insulation

Heating & Cooling Savings

• Reduces heat loss in winter by up to 50%
• Reduces heat gain in summer by up to 30%
• Lowers utility bills by 15-30% annually
• Reduces HVAC system runtime and wear
• Payback period typically 3-7 years

Health & Comfort Benefits

• Maintains consistent indoor temperatures
• Reduces cold spots and hot spots
• Improves indoor air quality
• Reduces noise transmission
• Prevents moisture problems and mold

Environmental Impact

• Reduces carbon footprint from heating/cooling
• Some insulation materials are recyclable
• Extends life of existing HVAC systems
• Contributes to green building certifications
• Reduces demand on power plants