Window Cleaning
Why Are My Windows Foggy? Condensation, Film or a Failed Seal
By Solpath Window Detailing · Published · Updated
If the fog is on the outside of the glass in the morning, it is condensation from warm, humid air meeting glass cooled by air conditioning, and it clears as the sun warms the pane. If it wipes off, it is film or residue. If it sits between the two panes of an insulated window and will not wipe off either side, the seal has failed and the glass unit needs replacing.
Where is the fog?
| What you see | What it is | What fixes it |
|---|---|---|
| Fog on the outside, early morning | Condensation on AC-cooled glass | Nothing needed; it clears as the glass warms |
| Haze that wipes off inside | Film from cooking, candles or sprays | A proper interior wash |
| Haze that wipes off outside | Salt, dust or sprinkler residue | An exterior wash; hard water treatment if it is mineral |
| Fog between the panes | A failed seal on an insulated unit | Replacing the glass unit |
| Haze that never changes, wet or dry | Etched glass | Nothing restores it fully |
Outside condensation is normal here
South Florida mornings are humid, and glass cooled by air conditioning overnight sits below the dew point. Moisture condenses on the outside face and burns off as the sun reaches it. It is not a defect, and it tends to be worst on well-insulated and impact windows, because they keep the cold inside where it belongs.
How to tell a failed seal
- The fog does not wipe off from inside or outside
- It comes and goes with temperature through the day
- You may see water droplets or a white residue between the panes
- It usually starts at the bottom edge or a corner
What we will tell you
A failed seal is a job for a glass company, and usually only the sealed glass unit needs replacing, not the whole window. If we find one while cleaning, we point it out rather than charge you to clean a pane that will stay foggy.
