Skip to content
CeilingTiles.us
Get installer quotes2x2 ceiling tiles2x4 ceiling tilesAcoustic ceiling tilesSee all: TilesDrop ceiling costHow to install a drop ceilingCeiling tile sizesSee all: GuidesCalculator

NRC vs CAC

By CeilingTiles.us editors · Updated · About us

NRC tells you how much sound a ceiling tile absorbs inside a room. CAC tells you how well the ceiling blocks sound traveling to the next room over the walls. They measure different things, and few tiles are great at both.

The ratings

Rating Range Higher means Good target
NRC: Noise Reduction Coefficient 0.00-1.00 More echo and noise absorbed 0.55-0.70 homes; 0.70+ theaters, open offices
CAC: Ceiling Attenuation Class ~20-40+ Less sound passes room-to-room through the plenum 35+ for offices, bedrooms
AC: Articulation Class ~150-200+ Better speech privacy in open offices 170+

Why you can’t have it all

Soft, porous materials (like fiberglass) absorb sound well (high NRC) but let sound pass through. Dense materials (heavy mineral fiber) block sound (high CAC) but reflect more. Some “combination” tiles balance both.

What to choose

  • Echoey room (basement rec room, home office): prioritize NRC.
  • Privacy between rooms (offices, bedrooms off a shared plenum): prioritize CAC, and add insulation above the tiles.
  • Noise from upstairs: tiles won’t fix impact noise; you need insulation and decoupled framing.

Browse acoustic ceiling tiles.

Frequently asked questions

Is NRC 0.70 good?

Yes: it absorbs about 70% of the sound that hits it, which is a big improvement in most rooms.

Questions from readers

Question about NRC vs CAC? Ask it here. We answer the useful ones on this page, in general terms.

Ask a question

We can’t reply privately. Useful questions get answered here on the page.