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Choosing Acoustical Ceiling Tiles: NRC Ratings for Offices, Schools and Healthcare

How to read NRC and CAC ratings and pick the right acoustical ceiling tile for San Antonio offices, classrooms and healthcare facilities.

By SCCI Drywall. Published 2026-10-22.

Key Takeaways

• NRC measures how much sound a tile absorbs inside a room, on a scale of 0 to 1.
• CAC measures how well the ceiling blocks sound traveling between rooms over a wall.
• Open offices and classrooms usually benefit most from high-NRC tiles.
• Private offices and exam rooms need attention to CAC and full-height walls for privacy.

Acoustical ceiling tiles do far more than cover ductwork. The right tile can make an open office feel calmer, help students hear their teacher, and keep a patient's conversation private. The wrong tile can leave a room echoing or let conversations drift over the wall to the next office. Two ratings tell you most of what you need to know: NRC and CAC.

NRC: Noise Reduction Coefficient

NRC measures how much sound a material absorbs instead of reflecting back into the room. It's expressed as a number between 0 and 1:

• NRC near 0: the surface reflects almost all sound, like painted drywall or glass.
• NRC around 0.50: the tile absorbs roughly half of the sound that hits it.
• NRC 0.70 and up: generally considered high-performance absorption.

Higher NRC tiles reduce echo and the buildup of background noise. They make the biggest difference in large, busy spaces where lots of people talk at once.

CAC: Ceiling Attenuation Class

CAC measures how well a ceiling blocks sound traveling from one room, up through the ceiling, across the open space above, and down into the next room. A higher CAC means better privacy between rooms that share a ceiling plenum. Dense tiles tend to score higher on CAC but lower on NRC, so the right tile depends on what each room needs most.

Picking Tiles by Space

Open Offices and Call Centers

Prioritize high NRC. Many conversations at once create a constant hum, and absorptive ceilings tame it.

Private Offices and Conference Rooms

Balance NRC and CAC. For true speech privacy, run the walls all the way to the structure above, because sound easily travels over a wall that stops at the grid.

Classrooms

Students need to hear clearly from every seat. High-NRC ceilings shorten echo time so the teacher's voice stays clear.

Healthcare

Exam rooms and consultation rooms need privacy, so CAC matters. Many healthcare areas also call for tiles that are washable, scrub-resistant or rated for cleanroom-type environments.

Other Factors Beyond Acoustics

• Humidity resistance: important in South Texas, especially in buildings where the HVAC cycles off overnight.
• Fire performance: some ceilings are part of rated floor-ceiling assemblies and must match the tested design.
• Light reflectance: brighter tiles bounce more light and can reduce lighting needs.
• Edge detail: square-lay-in tiles are simple and economical; tegular (recessed) edges give a more finished look.
• Grid: standard or narrow-face grid, and whether it needs to be heavy-duty for light fixtures and diffusers.

Grid Versus Hard Ceilings

Not sure whether you need a grid ceiling at all? Our article on drop ceilings versus drywall ceilings compares cost, access and acoustics. And if your current tiles are stained or sagging, see when to replace them.

Acoustical Ceilings in San Antonio

SCCI Drywall installs acoustical grid systems and ceiling tile for offices, schools, healthcare facilities and commercial spaces across San Antonio and South Texas. Call (210) 875-0280 to talk through your space.

Frequently Asked Questions

What is a good NRC rating for an office ceiling?

Many offices use tiles in the 0.55 to 0.70 range, while open offices and classrooms often benefit from 0.70 or higher.

What is the difference between NRC and CAC?

NRC measures sound absorbed inside a room. CAC measures how well the ceiling blocks sound passing between rooms through the space above.

Why can I hear the next office through the ceiling?

Often the wall stops at the ceiling grid, so sound travels over it. Running the wall to the structure above or using higher-CAC tiles helps.

Contact SCCI Drywall

SCCI Drywall serves San Antonio and all of South Texas with drywall installation, drywall repair, remodeling, metal stud framing, light gauge framing and acoustical grid ceiling systems for residential and commercial projects.

Phone: (210) 875-0280

Email: sccidrywall@gmail.com

Hours: Monday through Friday, 7:00 AM to 6:00 PM

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