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ROCKWOOL RXCB3523 COMFORTBATT R15 3.5 in. X 23 in. X 47 in. (60.06 SQFT)

ROCKWOOL RXCB3523 COMFORTBATT R15 3.5 in. X 23 in. X 47 in. (60.06 SQFT)

Best price now

$90.34at Go Build Supply & MoreObserved at 12:27 PM

Compared across 2 stores. Prices are checked against each store and labelled with when.

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Our take on the ROCKWOOL RXCB3523 COMFORTBATT R15 3.5 in. X 23 in. X 47 in. (60.06 SQFT)

ROCKWOOL Comfortbatt R-15 is semi-rigid stone wool batt insulation sized 3.5 x 23 x 47 in. for wood studs at 24 in. on center, about 60.06 sq ft per bag. It is noncombustible (ASTM E136) and rated 0/0 flame and smoke spread (ASTM E84), and its flexible edges are meant to fit wide bays without ripping. The best new price is $90.34 at Go Build Supply & More as of November 7, 2026, with two stores listing it new.

Best forFilling 24 in. on-center wood stud wallsGarages, basements and rim joists where fire resistance mattersDIYers who want batts that cut cleanly and hold shapeSound-damping interior walls
Pros
  • R-15 in a 3.5 in. cavity matches 2x4 framing
  • Stone wool is noncombustible and rated 0/0 for flame and smoke
  • 23 in. width suits 24 in. on-center bays, so less field ripping
  • Semi-rigid batts hold their shape and friction-fit between studs
  • GREENGUARD certified for indoor air quality
  • Cuts with a serrated blade and doesn't itch like fiberglass
Cons
  • Costs more per square foot than fiberglass batts of the same R-value
  • Denser and heavier per bag than fiberglass
  • Mineral wool can shed dust during cutting; wear a mask
  • Wrong width for 16 in. on-center walls; you need the 15.25 in. version

ROCKWOOL RXCB3523 COMFORTBATT R15 3.5 in. X 23 in. X 47 in. (60.06 SQFT) prices at every store

  • Go Build Supply & MoreNew

    Availability unknown

    $90.34+ $250.00 shippingObserved at 12:27 PM
    Visit Go Build Supply & More
  • McCoy's Building SupplyNew

    Out of stock

    $84.99Observed at 12:27 PM
    Visit McCoy's Building Supply

Also available at

  • YEARS BUILDING MATERIALSCheck price at YEARS BUILDING MATERIALS

ROCKWOOL RXCB3523 COMFORTBATT R15 3.5 in. X 23 in. X 47 in. (60.06 SQFT) price history

Lowest price we've seen: $84.99 on Nov 7 at McCoy's Building Supply. Tracked across 2 stores since Nov 7.

What reviewers say

Owners of ROCKWOOL Comfortbatt generally report easy friction-fit installation, clean cuts and noticeably quieter, warmer rooms. Complaints center on price versus fiberglass and on dust and itch during handling.

What people mention
  • InstallationPraisedOwners say the semi-rigid batts friction-fit between studs and need few staples.
  • CuttingPraisedReviewers report clean cuts with a serrated blade and little tearing at the edges.
  • SoundPraisedUsers say rooms are noticeably quieter than with fiberglass in the same walls.
  • PriceCriticisedBuyers note it costs more per square foot than fiberglass batts of equal R-value.
  • Dust and itchMixedSome owners complain of dust while cutting and skin irritation, though most say it is less itchy than fiberglass.
  • WeightCriticisedBags are heavier and denser than fiberglass, which some find harder to carry and place.

About the ROCKWOOL RXCB3523 COMFORTBATT R15 3.5 in. X 23 in. X 47 in. (60.06 SQFT)

About 60.06 sq ft per bag. RXCB3523 is Comfortbatt® R-15 at 3.5 × 23 × 47 in. for wood studs at 24 in. on center—ROCKWOOL documents the 24 in. o.c. wood module as 23 in. × 47 in. on the USA TDS (05-2025). Semi-rigid stone wool with flexible edges; noncombustible per ASTM E136 and 0/0 flame/smoke per ASTM E84. Reduces field ripping compared with forcing 15.25 in. batts into wide bays.

Specifications

Material
Mineral Wool
GREENGUARD Certified
Yes
Type
Thermal Type

Questions and answers

Is this the right width for my walls?
This 23 in. batt is for wood studs at 24 in. on center. For standard 16 in. on-center framing, buy the 15.25 in. Comfortbatt instead.
What R-value does it give in a 2x4 wall?
R-15 at 3.5 in. thick, which fills a standard 2x4 cavity. Deeper 2x6 walls need a higher-R product such as R-23.
How much does one bag cover?
About 60.06 sq ft per bag. Measure your wall area and add roughly 10 percent for cuts and waste.
Is it fire resistant?
Yes. ROCKWOOL lists it as noncombustible per ASTM E136 with 0/0 flame and smoke spread per ASTM E84.
Is it safe for indoor air?
It is GREENGUARD certified. Wear gloves, eye protection and a dust mask while cutting and installing.
When is the price lowest?
Insulation prices move with seasonal demand, often dipping outside peak building months. Compare the two new listings and check the price history before buying.
Where is the ROCKWOOL RXCB3523 COMFORTBATT R15 3.5 in. X 23 in. X 47 in. (60.06 SQFT) cheapest?
At Go Build Supply & More, for $90.34, as of our latest check.
Where can I buy the ROCKWOOL RXCB3523 COMFORTBATT R15 3.5 in. X 23 in. X 47 in. (60.06 SQFT)?
3 stores we checked sell it, including McCoy's Building Supply, Go Build Supply & More, YEARS BUILDING MATERIALS.

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