Confirm it is between the panes
Interior condensation on the room-side glass is humidity. Fog that you cannot wipe, trapped in the middle, is a failed seal.
Mineral haze and droplets that move slowly between panes are classic IGU failure.
Repair options
- Replace the IGU glass only if the frame is sound
- Full sash or full-frame replacement when frames are rotten or out of square
- Pair with siding when openings need flash rebuilt
Energy and comfort
A failed seal loses insulating gas and can raise condensation risk on the room side too.
We quote clear options — glass-only vs full unit — so you are not stuck with a surprise on install day.