Quick answer
If your window is foggy or has moisture you can’t wipe away, the haze is between the two panes of glass — a sign the sealed unit’s seal has failed. No amount of cleaning (inside or out) will fix it, because the surface isn’t the problem; the glass unit needs to be replaced. Cleaning only fixes haze and spots on the outer surfaces.
How to tell what kind of fog you have
Modern windows are sealed double- or triple-pane units with insulating gas between the panes. There are three kinds of “foggy”:
- Condensation on the inside surface (you can wipe it) — usually humidity in your home; common on cold Calgary mornings. Cleaning and managing indoor humidity helps.
- Film/spots on the outer surface (you can feel and clean it) — that’s dirt or hard-water deposits, and a proper clean fixes it.
- Haze between the panes (you can’t wipe it from either side) — a failed seal. The unit must be replaced.
Why a clean won’t fix a failed seal
When the seal around a sealed glass unit fails, the insulating gas escapes and moist air gets in, condensing as fog between the panes. Since that moisture is sealed inside the glass sandwich, you can’t reach it — only replacing the glass unit (not the whole window, usually) solves it.
What we can help with
We’ll happily tell you which type you have. If it’s surface haze, hard-water spotting or interior film, our interior and exterior cleans will make it crystal-clear. If it’s a failed seal, we’ll let you know honestly so you can call a glazier — no charge for a clean that wouldn’t help.
Not sure which you have?
Get a free quote and we’ll assess it — and clean what cleaning can fix.
Frequently asked questions
Why is my window foggy between the panes?
The sealed glass unit’s seal has failed, letting moist air in to condense between the panes. Cleaning can’t fix it — the glass unit needs replacing.
Can window cleaning remove fog inside the glass?
No. If the haze is between the two panes, it’s sealed inside and unreachable. Cleaning only fixes haze, dirt and hard-water spots on the outer surfaces.
How do I know if it’s condensation or a broken seal?
If you can wipe the moisture away, it’s surface condensation or dirt. If you can’t wipe it from either side, the seal has failed and the unit needs replacement.
