Rockwool Comfortbatt R-30 Attic Insulation vs ROCKWOOL Comfortbatt R23 Insulation

These are the same stone wool product line in two thicknesses, so the choice comes down to cavity depth. The R-30 Comfortbatt is the deeper batt for attics and 2x10 framing, where its higher R-value per square foot matters most. The R-23 RXCB551525 is the 5.5-inch batt sized for nominal 2x6 walls on 16-inch centers. Both are noncombustible, moisture-resistant and hold their shape well; owners of Rockwool batts consistently report easier cutting and less itch than fiberglass.

• Choose the Rockwool R-30 Comfortbatt if you are insulating an attic floor, a 2x10 wall or any cavity deep enough to take a thicker batt and you want the highest R-value per square foot.
• Choose the Rockwool R-23 RXCB551525 if you are filling nominal 2x6 wall cavities on 16-inch centers and need a batt that fits at full thickness.