Interior vs. Exterior Insulation: Which Suits Your Older Home?
Cologne – October 29, 2026 -- Interior insulation can raise the wall surface temperature in winter by around five degrees Celsius, cutting the risk of condensation and mold in older buildings without touching the facade.
Cold exterior walls encourage condensation and, with it, mold. Anyone who wants to prevent that and protect the building fabric should watch wall surface temperatures. Insulation can raise them, lower mold risk and reduce heat loss. The right choice between exterior and interior insulation depends on the building's structure, its facade and the effort involved.