PET Felt vs Other Acoustic Materials: What the Data Actually Says
A like-for-like look at recycled PET felt against wood slat, fibreglass and mineral wool, and acoustic foam — absorption, weight, handling, moisture and end of life.
CYC Acoustic Team
CYC Acoustic Panel Specialists
This is the short version of a longer set of comparisons on our site. For the full breakdown per material, see our comparison pages.
The one-line summary
PET felt wins on weight, handling, finish and end of life. Mineral wool wins on low-frequency absorption and on non-combustible options. Wood slat wins on rigidity and impact resistance. Foam is the cheapest and the weakest on fire behaviour.
Absorption per millimetre
| Material | Typical absorption | Notes |
|---|---|---|
| Recycled PET felt | Moderate to high, rising with thickness | Porous through its depth; no facing needed |
| Mineral wool / fibreglass | High, especially with depth and an air gap | Excellent low-frequency behaviour when thick |
| Wood slat | Varies enormously | Depends on slat spacing, battens and any backing — often a resonant absorber rather than a porous one |
| Acoustic foam | Moderate | Thin profiles absorb little; performance is profile-dependent |
Take any specific figure from the product's own test report. A category range is not a specification, and NRC is meaningless without the mounting condition it was measured under.
The practical differences
Weight. Felt is light, which matters on ceilings, on stud walls, and when one person has to carry a hundred of them up a stairwell. Wood slat and MDF-cored products are substantially heavier.
Handling. Felt cuts with a blade or scissors and does not shed irritant fibres the way mineral wool does. Mineral wool needs gloves, eye protection and respiratory protection when cut, and must be wrapped or faced so fibres do not migrate.
Finish. Felt is self-finished: the panel is the surface, available in many colours, and can be fluted, cut or shaped. Mineral wool almost always needs a fabric wrap, a perforated facing or a frame — an extra trade, an extra cost and an extra thing to get wrong.
Moisture. Felt does not swell when damp in the way an MDF core does. Mineral wool tolerates damp poorly if it stays wet and loses performance.
Impact. Wood slat and other rigid cores resist knocks better. Felt is softer and can be marked by sharp impacts at high-traffic heights.
End of life. Felt can be recycled where facilities accept it. Composite, faced and mineral products are usually harder to separate and therefore harder to recycle.
Where felt is the wrong choice
Being straight about this is more useful than a feature list:
- Deep bass control. If the problem is low-frequency build-up, thick mineral wool with a proper cavity will usually outperform felt at the same depth.
- High-impact areas. Corridors taking trolleys, school halls, sports facilities — a rigid core will survive better.
- Non-combustible requirement. If a project demands a non-combustible material, a polymer felt is not the answer, whatever its reaction-to-fire classification.
On fire claims
Fire performance is where comparisons are most often copied from one product page to another and least often verified. CYC Acoustic does not currently hold an ASTM E84 classification, and our reaction-to-fire classification is pending supplier test documentation. We publish no fire class until we hold the report. Ask every supplier for the report number before you rely on a claim — including ours.
How to decide
- Write down the symptom and the constraint (weight, moisture, impact, fire, budget)
- Eliminate materials that fail a constraint
- Compare the survivors on absorption at the depth you can afford
- Get the test reports
- Order a sample and look at the finish in your own light