Between the panes
Fog, haze or droplets inside the sealed cavity commonly indicate that the edge seal has lost its integrity. The surfaces cannot be wiped from the room.
The Sealed Glass Inside the Frame
Insulated Glass Units and Foggy Window Repair
Moisture trapped between panes often points to a failed insulated glass seal. If the sash and frame remain suitable, replacing the glass unit may solve the problem without replacing the complete window.
What an IGU Is
Two or more panes built as one sealed unit
An insulated glass unit—often shortened to IGU or called a sealed unit—uses multiple panes separated by a spacer around the perimeter. The enclosed space is kept apart from normal indoor and outdoor air.
The glass makeup may include a low-emissivity coating, gas fill, safety glass or other project-specific options. These details are part of the unit itself; the surrounding sash, frame, hardware and installation are separate parts of the window.
This distinction matters during repair. Cloudy glass does not automatically mean every part of the window has failed, but a clear pane does not prove the frame and installation are in good condition either.
Exterior pane
Sealed spacePerimeter spacer and seal
Interior pane
Where Is the Moisture?
Not all window condensation means a failed seal
The location and timing of moisture provide useful clues. An assessment is still needed when the cause is uncertain.
On the room side
Interior condensation relates to glass temperature, indoor humidity and airflow. It may occur even when the insulated glass seal is intact.
On the exterior
Temporary outdoor condensation can form when the outer pane becomes cooler than humid exterior air. It is not, by itself, proof of failure.
Repair or Replace?
Assess the glass and the window around it
The best scope depends on whether the existing components can continue to perform safely and reliably.
Replace the insulated glass unit
A made-to-measure sealed unit can often be installed into a serviceable sash or frame when the main problem is failed or damaged glass.
- Frame and sash remain sound
- Hardware still works appropriately
- Correct glass makeup can be identified
Replace the complete window
Full replacement may make more sense when deterioration, recurring water problems, poor operation or an unsuitable frame extends beyond the glass.
- Rot, distortion or significant damage
- Multiple failing components
- Opening or style needs to change
Made for the Existing Opening
Matching requires more than width and height
Replacement units are ordered to suit the window. Thickness, overall dimensions, spacer, pane type, coating location, tint and safety requirements may all matter.
Glass in doors, beside doors, close to floors or in other hazardous locations may need to meet safety-glazing requirements. Larger panes and specialty applications can have their own design constraints.
Windows Hamilton confirms the accessible details before ordering. Photos can help with initial triage, but they do not replace final measurement and inspection.
Helpful Details for Your Quote
What to send with a foggy-window request
Photos from inside and outside
Include the entire window and a closer image of the fogging, crack or affected edge rather than only a tight crop of the glass.
The number of affected units
Count separate panes or window sections. A wide combination window may contain several individual sealed units.
How the window operates
Tell us whether it is fixed, casement, awning, hung or sliding and whether locks, cranks or sashes currently work.
Any water or frame damage
Note staining, softness, swelling, loose trim or leakage during rain. These signs can change the recommended scope.
Clear the View, Choose the Right Scope
Request a Sealed-Unit Assessment
Seeing fog or moisture between your window panes?
Send Windows Hamilton photos of the full window, the affected glass and any labels or markings you can find. We will help determine whether the request should begin as insulated-glass replacement, window repair or complete replacement—without treating every cloudy pane as the same project.
Talk with our team: Call Windows Hamilton at 289-975-4020.