Insulation Calculator
Calculate insulation needs, R-values, and energy savings
Area to Insulate
Insulation Tips & R-Value Guide
Recommended R-Values by Zone:
- Zone 1-2 (Hot): Attic R-30, Walls R-13
- Zone 3-4 (Warm): Attic R-38, Walls R-13-15
- Zone 5-6 (Cold): Attic R-49, Walls R-20
- Zone 7-8 (Very Cold): Attic R-60, Walls R-21
• Higher R-values provide better insulation
• Seal air leaks before adding insulation
• Don't compress insulation - it reduces effectiveness
• Consider professional installation for spray foam
How to Use the Insulation Calculator
- Select space type: Choose from attic, walls, basement, or crawl space areas.
- Pick insulation type: Select fiberglass batts, spray foam, or blown-in insulation.
- Enter dimensions: Input length and width for each area to be insulated.
- Set current R-value: Enter existing insulation R-value if upgrading.
- Add energy costs: Input annual heating costs to calculate potential savings.
Understanding R-Values
What is R-Value?
R-value measures insulation's resistance to heat flow. Higher R-values provide better insulation. The "R" stands for resistance to heat transfer.
Recommended R-Values by Climate
Zone 1-2 (Hot Climates)
- • Attic: R-30 to R-49
- • Walls: R-13 to R-15
- • Floors: R-13
Zone 3-4 (Mixed Climates)
- • Attic: R-38 to R-60
- • Walls: R-13 to R-20
- • Floors: R-19 to R-25
Cold Climate R-Values
Zone 5-6 (Cold Climates)
- • Attic: R-49 to R-60
- • Walls: R-20 to R-21
- • Floors: R-25 to R-30
Zone 7-8 (Very Cold)
- • Attic: R-60
- • Walls: R-21
- • Floors: R-30
Types of Insulation & Applications
| Insulation Type | R-Value/Inch | Best For | Cost/Sq Ft |
|---|---|---|---|
| Fiberglass Batts | 3.2-3.8 | DIY installation, standard framing | $0.85-$1.45 |
| Blown-in Fiberglass | 2.2-4.3 | Attics, irregular spaces | $1.20-$2.80 |
| Cellulose | 3.6-3.8 | Blown-in applications, eco-friendly | $1.20-$2.40 |
| Spray Foam | 6.5-7.0 | Air sealing, irregular cavities | $3.50-$6.00 |
| Mineral Wool | 3.0-3.3 | Fire resistance, soundproofing | $1.35-$2.25 |
Insulation Installation Best Practices
Before Installation
- • Seal air leaks with caulk or weatherstripping
- • Ensure proper ventilation in attics
- • Check for electrical or plumbing obstacles
- • Wear protective equipment (mask, gloves)
- • Plan installation sequence
Installation Tips
- • Don't compress insulation - reduces R-value
- • Fill cavities completely without gaps
- • Cut batts slightly larger than cavity
- • Install vapor barriers on warm side
- • Maintain clearances around fixtures
Energy Savings & Payback
Potential Energy Savings
Attic Insulation
Can reduce heating/cooling costs by 10-50%
Wall Insulation
Typically saves 5-25% on energy bills
Floor Insulation
Can save 5-15% on heating costs
Factors Affecting Savings
- • Current insulation level
- • Local climate and energy costs
- • Home age and construction type
- • Air leakage and ventilation
- • HVAC system efficiency
- • Thermostat settings and usage patterns
Common Insulation Mistakes to Avoid
Installation Errors
- • Compressing insulation reduces effectiveness
- • Leaving gaps allows heat loss
- • Installing vapor barrier on wrong side
- • Blocking soffit vents in attics
- • Not sealing air leaks first
Planning Mistakes
- • Choosing wrong R-value for climate
- • Not considering moisture issues
- • Ignoring thermal bridging
- • Inadequate insulation around fixtures
- • Not planning for future access needs
Safety & Health Considerations
Important Safety Note
Always wear proper protective equipment when handling insulation. Some materials can cause skin irritation and respiratory issues.
Protective Equipment
- • N95 or better dust mask
- • Safety glasses or goggles
- • Long sleeves and pants
- • Work gloves
- • Sturdy shoes with good traction
Work Area Safety
- • Ensure adequate lighting
- • Watch for electrical hazards
- • Use proper ladder safety
- • Ventilate work area
- • Keep emergency contact information handy
Related Construction Calculators
Frequently Asked Questions
What R-value do I need for my climate?
R-value requirements vary by climate zone. Check the DOE recommendations or local building codes for your specific area.
Can I install insulation myself?
Fiberglass batts are DIY-friendly, but blown-in and spray foam typically require professional installation and equipment.
How long does insulation last?
Most insulation lasts 20-30 years. Fiberglass and mineral wool can last longer, while cellulose may settle over time.
Should I remove old insulation before adding new?
Not always necessary. You can often add new insulation over old, but remove damaged or contaminated insulation first.