Types of Insulation Materials

Closed-cell foam boards: Excellent R-value, blocks air/moisture, can be cut to fit. Common types are polyisocyanurate & extruded polystyrene. Thermal Acoustic Liner

Fiberglass batts: Flexible insulation for filling wall cavities. Affordable but can irritate skin/lungs if fibers are exposed.

Open-cell spray foam: Conforms to any shape and air seals. More expensive initial cost. Vulnerable to moisture if not protected.

Rock wool: Mineral-based batts with good fire resistance. Can absorb more moisture than fiberglass. May crack over time.

Cellulose insulation: Made from recycled materials, eco-friendly. Must be properly enclosed to prevent settling. May harbor mold/pests.

Reflective insulation: Foil-faced sheeting reflects radiant heat. Good layered under other materials. Can tear or condense moisture.

Denim/cotton insulation: Jeans and clothing recycled into batts. Less itchy than fiberglass. May compress more than mineral wools.

Phase-change materials: Absorb/release latent heat during melting. Best for intermittent heating applications. Higher costs.


Eco-friendly since it recycles old jeans and clothes. Softer and less itchy than fiberglass, so easier to handle. Breathable material allows moisture to escape. Affordable price compared to some insulation options. Thermal Insulation Sheet


May compress more over time than mineral wool or foam options. Absorbs moisture more easily than rigid materials if exposed. Combustible material so needs fire blocking in walls. Requires encasement to prevent fibers from spreading. Difficult to get full coverage in some insulation cavities.


Denim/cotton insulation provides decent insulation value for the cost. But it isn’t as durable or rigid as fiberglass or foam boards, which maintain full thickness longer.

Its breathability could help reduce condensation compared to impermeable options. However, it requires more care in installation to prevent moisture issues or fiber migration long-term. Its eco-friendly aspect may outweigh the disadvantages for some users.

Fiberglass or Foam Boards:

Fiberglass batt insulation typically has an R-value of R-3-3.5 per inch. Fiberglass offers consistent performance at a lower cost than some options.

Foam boards like polyisocyanurate and extruded polystyrene range from R-4-6 per inch, making them some of the most effective insulators for their thickness.

Denim/cotton insulation has an R-value of around R-2-3 per inch. While it provides some benefits, the insulation performance is not as high.

Some Key Points of Comparison:

Fiberglass and foam boards maintain their thickness and R-value longer due to their rigid structure.

Compression over time can reduce denim/cotton’s R-value more noticeably.

Multiple layers may be needed to achieve the same R-value as one layer of foam or fiberglass.

Fiberglass and rigid foam are better choices for applications where maximum insulation is critical.


Denim/cotton R-2-3 per inch
Fiberglass R-3-3.5 per inch
Foam boards R-4-6+ per inch


Denim/cotton is one of the most affordable options ($0.80-$1.50 per square foot)

Fiberglass is also inexpensive ($1-2 per square foot)

Foam boards range from $1.50-4 per square foot depending on the thickness


Denim works well for floors, attics, and some wall cavities
Fiberglass is best for standard wall and ceiling installations
Foam excels at rim/band joists, basements, roof decks


Denim has a softer look and feel than fiberglass
Foam boards provide a seamless appearance
Fiberglass can be concealed for aesthetics


Denim, fiberglass can be cut with scissors, knife
Foam requires a saw, and knives for clean cuts

Moisture Resistance:

Denim/cotton absorbs moisture more readily than fiberglass or foam boards. Fiberglass and foam are more resistant to wicking/holding moisture over time.

Air Sealing:

Denim/cotton is less effective at air sealing than closed-cell foam options. Fiberglass allows more airflow than rigid boards but can be sealed with dense packing.


Denim performs better as a sound insulator than fiberglass due to its density. Foam boards provide excellent sound blocking when installed correctly.

Health & Safety:

Denim/cotton fibers may cause less irritation than exposed fiberglass particles. Improperly installed foam carries the risk of toxic off-gassing.


Denim requires care to fill cavities fully and avoid settling over time. Fiberglass and foam provide more continuous insulation surfaces.


Fiberglass and foam maintain R-values longer with less compression over decades. Denim/cotton R-value may degrade quicker depending on moisture, and loads.

Environmental impact:

Denim/cotton insulation diverts textile waste from landfills, making it eco-friendly. However, cotton production still uses lots of pesticides and water. Fiberglass production requires energy but the materials are highly recyclable at end-of-life. Foam manufacturing involves ozone-depleting blowing agents. Some foams use hydrofluoroolefin instead of CFCs.

Long-term costs:

Denim may need replacement sooner if it compresses or gets wet over decades. Fiberglass and foam will maintain R-value longer with less maintenance/replacement required.

Code compliance:

Denim/cotton meets the code unless the fire-rated assembly is required. Fiberglass and foam boards are available with fire barriers for required assemblies.


DIYers can stuff jean legs/rags for unique projects. Foam cut/shaped precisely, fiberglass jammed into any cavity.

So in summary, multiple factors determine the best material – project needs, budget, codes, and environmental priorities all shape the decision. Combining materials utilizes each type’s strengths.