Do Acoustic Panels Help With Insulation?
Updated
Acoustic panels help with insulation only a little: a 2 in. fiberglass panel core is rated R-8.7, but two 2 x 4 ft panels on a 12 x 8 ft R-13 outside wall cut the heat going through that wall by about 7%. So do acoustic panels insulate heat? The core does, but the panels cover too little of the wall to show up on your energy bill.
Owens Corning rates its 703 board, a common panel core, at R-4.3 per inch: R-4.3 at 1 in. and R-8.7 at 2 in. (703 data sheet (opens in a new tab)). Foam panels are sold on sound alone, with no published R-value. You can compare the cores in fiberglass and mineral wool soundproof panels.
Example: Heat flow is proportional to area divided by R-value. Bare wall: 96 ÷ 13 = 7.38. With two panels: 80 ÷ 13 + 16 ÷ (13 + 8.7) = 6.15 + 0.74 = 6.89, which is 93% of 7.38. This math ignores studs, windows and air films, so use it to compare, not to predict your bill.
On an inside wall between two heated rooms, the savings drop to almost nothing. Heat "flows from warmer to cooler areas until there is no longer a temperature difference," as the Department of Energy (opens in a new tab) puts it, and two heated rooms don't have much of a difference to slow down.
Want a warmer room? DOE points you to air sealing and cavity insulation instead. Buy panels for echo, as the soundproof panels guide explains. Those same fiberglass and stone wool cores also rate well for fire, which are acoustic panels fire resistant covers. More answers are in the soundproof panels FAQ.