Walk into any office supply store or scroll through Amazon and you'll find acoustic foam panels everywhere. They're cheap, they come in fun colors, and the marketing says they'll fix your noise problems. Then there's felt — specifically PET felt and wool felt — which costs more but shows up on architect specs for commercial projects. What's the actual difference? We install felt panels in commercial buildings every week. Here's the honest comparison.
What Are We Comparing?
Felt panels: Pressed PET (recycled polyester) or wool fiber panels, typically 9mm–24mm thick. Commercial-grade products from manufacturers like FilzFelt, Baux, Zintra, and others. Density ranges from 1.5–4 lb/ft³. Available in sheets, tiles, and custom shapes.
Foam panels: Open-cell polyurethane or melamine foam, typically 1"–2" thick. The pyramid/wedge-shaped panels you see in recording studios and on Amazon. Density is usually 1–2 lb/ft³. Also includes higher-end melamine foam (like Auralex) for studio applications.
Acoustic Performance (NRC)
| Material | Thickness | NRC |
|---|---|---|
| PET Felt (9mm) | ~3/8" | 0.30–0.40 |
| PET Felt (12mm) | ~1/2" | 0.40–0.55 |
| PET Felt (24mm) | ~1" | 0.60–0.80 |
| Acoustic Foam (1") | 1" | 0.30–0.50 |
| Acoustic Foam (2") | 2" | 0.65–0.85 |
| Melamine Foam (2") | 2" | 0.85–0.95 |
Thickness for thickness, foam absorbs more sound — it's less dense, so sound waves penetrate deeper. But here's the thing: in a real commercial space, you're covering walls with panels, not building a recording booth. Felt panels at 12mm or thicker provide plenty of absorption for office noise, conference rooms, and open-plan areas. You don't need NRC 0.90 on every wall.
Verdict: Foam wins on raw NRC per inch. Felt at 12mm+ is adequate for most commercial applications.
Fire Safety
This is where felt pulls ahead and it's not even close for commercial work.
Felt (PET): Most commercial PET felt panels are Class A fire-rated (ASTM E84: flame spread ≤25, smoke developed ≤450). They self-extinguish. This matters because commercial building codes require Class A materials on walls in most occupancies — offices, schools, healthcare, retail, government buildings.
Foam: Standard polyurethane foam is highly flammable. It ignites easily, burns fast, and produces toxic smoke. This is a serious safety issue. Higher-end melamine foam (Auralex, Sonex) has better fire performance but still typically rates Class B or Class C. Some foam products have fire-retardant treatments, but even treated foam rarely achieves Class A.
Verdict: Felt wins decisively. For any commercial installation, you need Class A materials. Foam rarely qualifies. Building inspectors will flag non-rated acoustic foam on commercial walls.
Durability
Felt: Dense, tough, and long-lasting. PET felt doesn't crumble, tear easily, or degrade with UV exposure. You can vacuum it, spot-clean it, and it holds its shape for 15–20+ years. It resists moisture (PET doesn't absorb water) and doesn't support mold growth.
Foam: Fragile. Acoustic foam crumbles over time, especially in high-traffic areas. People brush against it, it tears. UV light degrades it — foam panels near windows turn yellow and disintegrate within 2–3 years. It absorbs moisture and can develop mold in humid environments. Most foam panels start looking rough after 3–5 years.
Verdict: Felt wins. Dramatically more durable in real-world commercial environments.
Aesthetics
Felt: Looks professional. Clean edges, consistent texture, available in 40+ colors. Can be cut into custom shapes — hexagons, triangles, wavy panels, brand logos. Felt tiles create visually interesting feature walls that architects love to spec. The material has a sophisticated, textile feel.
Foam: Looks like a recording studio. Pyramid and wedge patterns are unmistakably "acoustic treatment" — which is fine in a studio but looks out of place in an office lobby or conference room. Flat foam panels are less obtrusive but still look like foam. Color options are limited (usually charcoal, black, or a few bright colors).
Verdict: Felt wins for any space where appearance matters. Foam is acceptable in back-of-house, studio, or mechanical rooms.
Cost
| Product | Material $/sf | Installed $/sf |
|---|---|---|
| PET Felt (12mm tiles) | $4–$8 | $8–$15 |
| PET Felt (custom shapes) | $8–$15 | $15–$25 |
| Wool Felt (premium) | $10–$20 | $18–$30 |
| Acoustic Foam (1") | $1–$3 | $3–$6 |
| Melamine Foam (2") | $4–$8 | $8–$14 |
Foam is cheaper, no question. Basic acoustic foam costs a fraction of what felt costs. But when you factor in replacement every 3–5 years (foam deteriorates), felt's 15–20 year lifespan makes it cheaper over the long run.
Verdict: Foam wins on upfront cost. Felt wins on lifecycle cost.
Sustainability
Felt: PET felt is made from recycled plastic bottles — typically 50–80% recycled content. It's recyclable at end of life. No VOC emissions. Contributes to LEED credits for recycled content and low-emitting materials.
Foam: Made from petroleum-based polyurethane. Low recycled content. Not recyclable in most municipalities. Some foam products off-gas VOCs, especially when new.
Verdict: Felt wins. Better recycled content, lower environmental impact.
Our Recommendation
For commercial spaces: Felt. Every time. Fire safety alone eliminates foam from most commercial applications. Add durability, aesthetics, and sustainability on top of that, and felt is the clear choice for offices, schools, healthcare, retail, and hospitality.
When foam makes sense: Recording studios, home theaters, podcast rooms, and other non-commercial spaces where fire code isn't enforced and appearance is secondary to maximum absorption per dollar. Even then, we'd suggest looking at 24mm PET felt — it looks better and lasts longer.