Determine how much insulation you need and the estimated cost for your project.
This calculator helps you estimate insulation material needs and rough total project cost for attics, walls, and similar spaces.
Imagine you want to upgrade a 1,000 square foot attic to roughly R-38 using blown-in cellulose.
Because cellulose is often one of the lower-cost upgrade paths, it can be a practical way to improve comfort and energy efficiency without jumping immediately to spray foam pricing.
| Material | R-Value per Inch | Cost per Sq Ft (R-38) | Pros | Cons | Best For |
|---|---|---|---|---|---|
| Fiberglass Batts | 3.0-3.8 | $0.90 | Affordable and DIY-friendly | Can lose effectiveness if poorly installed | Attics and basic wall projects |
| Spray Foam | 6.0-7.0 | $3.00 | High R-value and strong air sealing | More expensive | Air sealing and compact spaces |
| Cellulose | 3.2-3.7 | $0.50 | Good value and recycled content | Usually requires blower equipment | Attics and retrofit work |
| Rigid Foam Board | 4.5-6.0 | $1.50 | Moisture resistant and easy to cut | Needs careful seam treatment | Basement walls and specialty applications |
This calculator treats R-value as the main planning benchmark because that is how insulation performance is commonly explained in homeowner-facing technical guidance. The U.S. Department of Energy's insulation overview and its page on insulation types are useful reference points because they explain where different materials are typically used, how thermal resistance is compared, and why the right target depends on assembly type and climate.
We use those references to keep the calculator anchored to common residential planning logic, but the output is still only a baseline. Final insulation decisions should also account for air sealing, moisture control, venting strategy, local code, and the depth available in the actual wall, roof, or floor assembly.
Basic fiberglass work can be approachable for DIYers, but complicated assemblies often benefit from professional installation and moisture planning.
Many homes target somewhere between R-38 and R-60, depending on the climate and local recommendations.
Often yes, if the existing material is dry and in good condition. Moisture-damaged insulation should be addressed before adding more.
Fiberglass is often the easiest DIY option, while spray foam usually requires professional handling.
If you are estimating a specific attic scenario, use this focused guide first and then confirm the full project in the calculator.
Disclaimer: This calculator provides planning estimates only. Actual insulation costs vary by climate zone, product density, required thickness, labor rates, access difficulty, and local code requirements. Always verify assembly details before purchasing materials.
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