Peninsula Insulation, LLC

Adding more insulation sounds simple, but stacking fiberglass over old material can create hidden problems. In many homes, the issue is not insulation depth but air leakage and moisture movement. Understanding when adding fiberglass helps, and when it hurts, protects energy performance and building health. Quick answers that matter most Adding fiberglass can help only if the existing insulation is dry and intact. Air leaks limit performance, no matter how much fiberglass is added. Spray foam often solves problems fiberglass cannot fix. More Fiberglass = Limited Gains Adding fiberglass insulation over existing layers can improve R-value, but it does not stop air movement. Fiberglass slows heat transfer, yet air can still pass through it. If the original insulation has gaps, compression, or moisture damage, adding more material hides the problem instead of fixing it. This leads to ongoing heat loss and uneven indoor temperatures. According to guidance from the U.S. Department of Energy,...