The short answer
Insulated glass uses two or more panes separated by a sealed space. Persistent haze, droplets, or mineral-like residue that cannot be wiped from either exposed glass surface can indicate that moisture has entered that sealed space. Confirm the location first, identify the exact product and warranty, then compare glass-unit, sash, or full-window service options based on product design and the condition of the frame and opening.
Confirm where the moisture is
- Clean and dry the room-side and outdoor surfaces when safely accessible.
- Photograph the haze at different times and lighting conditions.
- Check whether it remains between the panes rather than on an exposed surface.
- Record the product label, order information, approximate installation date, and affected openings.
- Inspect the sash, frame, perimeter, and nearby finishes for separate damage or water entry.
Compare the available service scope
| Compare | Scope | Questions |
|---|---|---|
| Insulated glass unit | Can the sealed glass be replaced in the existing sash? | Who measures, reglazes, and warranties the work? |
| Complete sash | Is a compatible sash available? | Does it include the correct glass, finish, hardware, and weatherstripping? |
| Complete window | Is the frame or operation also unsuitable? | Will the work be insert or full-frame and what opening repairs are included? |
Common questions
Common questions
Can fog between panes be wiped away?
Not when the moisture or residue is inside the sealed space. Verify both exposed surfaces before concluding that the sealed glass is affected.
Sources
Sources
- Window Types and Technologies — U.S. Department of Energy
- Window Energy Performance Ratings — National Fenestration Rating Council
- A Brief Guide to Mold, Moisture and Your Home — U.S. Environmental Protection Agency