Insulation R-Value Comparison: Complete Product Database

R-Value Chart: All 29 Products

Sorted by total R-value (highest first). Color indicates type: ■ batt ■ spray foam ■ rigid board ■ blown-in

Full Comparison Table

Analysis by Insulation Type

Fiberglass Batts — Best R-value per dollar

Fiberglass batts remain the lowest-cost option per dollar of R-value. R-19 from Owens Corning runs $0.85–$1.20/sq ft. The Knauf EcoBatt R-13 is the cheapest batt in the database at $0.50–$0.85/sq ft — about $0.065 per R-point per sq ft. Standard 2×4 framing (3.5") fits R-13; 2×6 framing (5.5") fits R-19 to R-21.

For highest R-value in a batt, Johns Manville's R-38 kraft-faced attic batt achieves R-38 at 12" thickness — designed for attic floor applications, not wall cavities. At $1.25–$1.85/sq ft it's still cheaper per R-point than spray foam. See all Johns Manville products.

Blown-In — Best for retrofits and attics

Blown-in fiberglass achieves R-30 at similar or lower cost than batts: the JM Climate Pro tops out at $0.65–$0.95/sq ft for R-30. The advantage over batts is that blown-in fills irregular cavities and existing attic floors without demolition. Attic coverage: ~65–72 sq ft per bag at R-30 depth, depending on product. Requires a blowing machine (rental or contractor-owned). See all insulation products.

Closed-Cell Spray Foam — Best R-value per inch

Closed-cell spray foam achieves R-6 to R-7 per inch, versus R-3.2 per inch for fiberglass. The tradeoff is cost: $1.65–$2.80/sq ft vs $0.50–$1.85/sq ft for batts. At 2" thickness, closed-cell spray foam achieves R-13 to R-14 — same as a 3.5" batt, but half the thickness. The HFO blowing agents (GWP of 1) in newer products like Huntsman HFO and SES Foam HFO Pro are an environmental improvement over older HFC-245fa foam. See Huntsman products.

Rigid Board — Continuous insulation and thermal breaks

Rigid board is not competing with batts for cavity fill — it's for continuous insulation on the building exterior, breaking thermal bridges through studs. Rockwool ComfortBoard 80 at R-8 and Dow STYROFOAM at R-10 are used in walls over sheathing. Polyiso (GAF EnergyGuard, Atlas EnergyShield) achieves R-10+ at 3" for roofing applications. Pricing looks high ($22–$68/sq ft for some) because these are roofing-grade products with different unit economics than residential wall insulation.

The aerogel outlier — Aspen Aerogels Cryogel Z — achieves R-10 at just 10mm (0.4") thick. That's ~R-25 per inch. Price ($8–$15/sq ft) reflects the technology. Used in industrial and retrofit applications where space is a hard constraint. See Aspen Aerogels.

R-Value Requirements by Climate

DOE climate zone recommendations for new construction (attic / wall / floor):

ci = continuous insulation. Source: DOE IECC 2021 reference values.

Query R-Value Data via API

The Substrata API returns r_value, thickness_mm, price_min_usd, and price_max_usd for every insulation product. Use it to build your own comparison tools or feed estimating software.

GET /v1/products?category=insulation&min_r_value=19
Authorization: Bearer sk_sub_your_key

// Returns all insulation products with R-19 or higher
// Fields: name, manufacturer, r_value, thickness_mm,
//         price_min_usd, price_max_usd, price_unit, specs

Related Reading

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• Building Product Specifications API — querying R-values and other specs programmatically
• Insulation category page — browse all 36 products