Your attic is one of the most important areas to insulate. Heat rises, and an under-insulated attic can account for 25-30% of your home's total heat loss. Choosing the right insulation can significantly reduce energy bills and improve comfort. This guide compares the top attic insulation options to help you make the best choice.
Why Attic Insulation Matters
Before comparing options, it's important to understand why attic insulation is so critical:
- Heat loss prevention: In winter, warm air rises and escapes through an under-insulated attic
- Cooling efficiency: In summer, attics can reach 150°F+, radiating heat down into living spaces
- Moisture control: Proper insulation helps prevent condensation and ice dams
- Energy savings: Attic insulation upgrades typically provide the best ROI of any home improvement
Recommended R-Values for Oklahoma Attics
The Department of Energy recommends the following R-values for attics in Oklahoma (Climate Zone 3-4):
- Minimum: R-38
- Optimal: R-49 to R-60
Keep these targets in mind as you compare insulation options—each type requires different thicknesses to achieve these R-values.
Attic Insulation Options Compared
1. Spray Foam Insulation
Spray foam has become the gold standard for attic insulation due to its superior performance characteristics.
Advantages
- Highest R-value per inch (R-3.7 to R-6.5)
- Complete air sealing—no gaps or voids
- Doesn't settle or degrade over time
- Can create conditioned attic space
- Reduces HVAC sizing requirements
- Deters pests and moisture
Considerations
- Higher upfront cost
- Requires professional installation
- Difficult to modify after installation
Best for: Homeowners seeking maximum energy efficiency, conditioned attic spaces, or those with complex roof structures. Ideal for new construction and major renovations.
Cost: $1.00-$2.50 per square foot installed
2. Blown-In Fiberglass
Blown-in fiberglass is a popular choice for retrofitting existing attics due to its ease of installation.
Advantages
- Lower upfront cost
- Easy to install in existing attics
- Non-combustible
- Won't absorb moisture
- Can be DIY installed (though not recommended)
Considerations
- Lower R-value per inch (R-2.2 to R-2.7)
- Settles over time (10-20% loss)
- Doesn't air seal
- Requires 13-17 inches for R-38
- Can lose effectiveness when compressed
Best for: Budget-conscious homeowners with standard attic configurations and adequate headroom.
Cost: $0.50-$0.90 per square foot installed
3. Blown-In Cellulose
Made from recycled newspaper treated with fire retardants, cellulose is an eco-friendly option.
Advantages
- Made from 80%+ recycled materials
- Good R-value (R-3.2 to R-3.8 per inch)
- Better at filling gaps than fiberglass
- Affordable
- Natural pest deterrent
Considerations
- Absorbs and retains moisture
- Settles significantly over time
- Heavy when wet (can damage ceilings)
- Requires 10-14 inches for R-38
- May need reapplication after years
Best for: Environmentally conscious homeowners in dry climates with good attic ventilation.
Cost: $0.60-$1.00 per square foot installed
4. Fiberglass Batts
Traditional pink batts are the oldest insulation type still in common use.
Advantages
- Lowest material cost
- Easy to find at any hardware store
- DIY-friendly for simple installations
- Won't absorb moisture
Considerations
- Difficult to install without gaps
- Lower R-value (R-2.9 to R-3.8 per inch)
- Compressed batts lose effectiveness
- No air sealing capability
- Prone to moisture damage
- Can sag and develop gaps over time
Best for: New construction with standard joist spacing and no obstructions, or as a budget option for DIYers.
Cost: $0.30-$0.50 per square foot installed
5. Radiant Barrier
Radiant barriers are reflective materials that reduce heat gain from the roof, not traditional insulation.
Advantages
- Reduces attic temperatures by 20-30°F
- Most effective in hot, sunny climates
- Works well in combination with other insulation
- Relatively affordable
Considerations
- No R-value—doesn't prevent conductive heat loss
- Less effective in cold climates
- Dust accumulation reduces effectiveness
- Must be combined with traditional insulation
Best for: Use as a supplement to other insulation in hot climates, particularly with cooling-dominated energy bills.
Cost: $0.15-$0.40 per square foot installed
Side-by-Side Comparison
Choosing the Right Insulation for Your Attic
Consider these factors when making your decision:
Your Budget
If upfront cost is the primary concern, blown-in fiberglass or cellulose offer the best value. However, factor in long-term energy savings—spray foam often pays for itself within 5-7 years through reduced utility bills.
Your Climate
In Oklahoma's climate with both hot summers and cold winters, insulation that provides both thermal resistance AND air sealing delivers the best year-round performance. Spray foam excels in this area.
Your Attic Type
- Unconditioned attic (insulation on floor): Blown-in or batts can work well
- Conditioned attic (insulation at roofline): Spray foam is the best choice
- Finished attic (living space): Spray foam or dense-pack cellulose
Air Sealing Needs
If your home has significant air leaks (common in older homes), spray foam addresses both insulation and air sealing in one application. With other insulation types, you'll need to pay for separate air sealing work.
Not Sure Which Insulation is Right for Your Attic?
Our insulation experts can assess your attic and recommend the best solution for your home, budget, and energy goals. Schedule a free consultation today.
Our Recommendation
For most Oklahoma homeowners, we recommend:
- Best overall: Closed-cell or open-cell spray foam at the roofline creates a conditioned attic space, protecting ductwork and maximizing HVAC efficiency
- Best budget option: Blown-in fiberglass or cellulose on the attic floor, combined with air sealing at penetrations
- Best for existing insulation: Add blown-in insulation on top of existing batts to reach R-49+
The "best" insulation ultimately depends on your specific situation. A professional assessment can identify the most cost-effective solution for your home.
Common Attic Insulation Mistakes to Avoid
- Blocking soffit vents: Maintain airflow from soffit to ridge for unconditioned attics
- Compressing insulation: Compressed batts lose R-value significantly
- Ignoring air sealing: Insulation alone doesn't stop air leaks
- Insufficient coverage: Thin spots and gaps compromise the entire system
- Covering recessed lights: Non-IC rated fixtures are fire hazards when insulated