Older homes are often the worst insulated — and the hardest to fix. Balloon framing, no vapor barriers, plaster walls, and knob-and-tube wiring all create constraints that newer homes don't have. Here's how to approach it.
Homes built before 1980 were designed when energy was cheap. Wall cavities may be partially filled with old fiberglass, vermiculite, or nothing at all. Attics often have 2–3 inches of loose fill that's settled and degraded. Air sealing was never part of the original build.
The attic is always the first place to insulate in an older home. It's the highest ROI, hardware storest risk, and easiest access point. If existing insulation is below R-22, add blown-in or batt insulation on top. Target R-38 to R-60 depending on your climate zone.
Adding wall insulation to an existing home means either blowing in loose fill through holes drilled in the siding or drywall, or tearing out walls. Blown-in cellulose or fiberglass is most common for retrofits. Mineral wool batts work well when walls are opened during renovation.
Many older homes have knob-and-tube wiring, which must not be covered with insulation — it needs air circulation to dissipate heat. Have an electrician assess and upgrade the circuit before insulating. Most insurers require this anyway.
Old homes often have no vapor barrier. Adding insulation without addressing moisture can trap water inside walls. In cold climates, install kraft-faced batts or a polyethylene barrier on the warm side of the insulation. In hot climates, a vapor barrier on the exterior side is correct.
We supply R-11, R-13, R-15, R-19, and R-21 fiberglass batts for wall retrofits, and R-30, R-38, and R-49 for attic top-ups. Mineral wool is ideal for older homes with noise or fire concerns. Call us with your square footage and we'll quote the right quantity.
We supply wholesale fiberglass and mineral wool insulation with next-day delivery across all 50 states. Call us or request a quote online.