Haze between panes
A cloudy film that cannot be wiped from either accessible surface is a common sealed-unit symptom.
Condensation or haze between panes
Foggy window glass usually means a failed sealed unit
When moisture, haze or mineral staining appears between panes, cleaning the room-side surfaces will not solve it. The estimator focuses on replacing the insulated glass unit while checking whether the sash and frame can remain.
Toronto & GTAPhoto review availablePlanning range first
Recognize the scope
Separate a sealed-unit failure from room-side condensation
Fog or droplets trapped between panes indicate that the perimeter seal has failed and outside moisture has entered the insulated unit. Condensation on the room-side surface can instead relate to indoor humidity, ventilation or cold interior glass.
A photo taken from an angle, plus an edge view showing the spacer, helps distinguish the conditions. The frame, sash, hardware and drainage should also be reviewed before deciding that glass-only replacement is enough.
Planning rule: homeowner measurements and photos support the online range, but custom manufacturing dimensions and specifications must be confirmed before ordering.
Common project paths
Choose the condition that best matches what you see
Do not worry if you do not know the technical glass or hardware name. The estimator uses the visible condition first, then asks for the details that matter.
Sound frame and sash
When the operating unit remains solid, glass-only replacement may be the appropriate scope.
Hardware or seal problems too
Poor closing, damaged operators or drainage issues may need separate repair.
Uncertain moisture source
Use photos and note when the condensation appears if you are not sure which surface is wet.
Range logic
Why two foggy windows can have different ranges
The replacement unit is custom-made. Size, thickness, coatings, grids, shape and access all influence the supply and installation scope.
01
Unit sizeWidth, height and thickness affect glass area, weight and handling.
02
Glazing packageDouble or triple glazing, Low-E surfaces, gas fill and warm-edge spacers change the unit.
03
Grid configurationGrids between glass, surface bars or decorative patterns may require matching.
04
Sash conditionDamaged stops, rot, warping or drainage issues can expand the repair beyond the sealed unit.
Information that narrows the range
Four inputs that prevent one-size-fits-all pricing
Known dimensions, product construction and site conditions produce a tighter planning range. Unknown answers remain available, but the result may be wider.
Width, height and thickness affect glass area, weight and handling.
Double or triple glazing, Low-E surfaces, gas fill and warm-edge spacers change the unit.
Grids between glass, surface bars or decorative patterns may require matching.
Damaged stops, rot, warping or drainage issues can expand the repair beyond the sealed unit.
Estimate to confirmation
A practical process before custom material is ordered
1
Identify the affected unit
Count the foggy openings and note whether each is fixed, casement, awning, slider or another style.
2
Add reference measurements
Approximate daylight or sash dimensions help planning, but fabrication sizes must be professionally confirmed.
3
Check the surrounding window
The final review confirms the sash, stops, drainage, hardware and exact insulated glass construction.
Toronto and GTA conditions
Older Toronto windows may combine glass failure with other wear
A foggy unit can be the only defect, but older windows may also have weak operators, failed weather seals, loose hardware or deteriorated wood. The page keeps those conditions separate so glass replacement is not automatically treated as a complete window replacement.
Related project paths
Compare the scope before choosing the category
Window Replacement
For frames or complete units that have reached the end of service life.
Explore this page →
Glass Replacement
For cracked, broken or specialty glass beyond foggy sealed units.
Explore this page →
Free GlassQuote.ca resources
Tap a cover. Open the guide you need.
Swipe through the three homeowner guides or open any PDF directly.
Buying Guide
Compare products, installation methods, contractor quotes and warranties.
Measurement Guide
Record useful preliminary measurements without treating them as final order sizes.
2026 Cost Guide
Plan a realistic budget by style, size, quantity, glazing and installation scope.
Frequently asked questions
What to know before requesting the estimate
Can a foggy window be resealed instead of replacing the unit?
Services that vent or defog a failed unit may improve appearance temporarily but do not recreate the original factory seal or insulating performance. Replacement of the insulated glass unit is the usual permanent scope.
Does fog between panes mean the whole window must be replaced?
Not necessarily. If the sash and frame are sound, the sealed glass unit can often be replaced separately.
Can the new unit match the existing Low-E tint?
A close match is often possible, but exact colour can vary by manufacturer, coating generation and the age of adjacent glass.
Should every foggy unit in the house be replaced together?
No. Each opening can be assessed separately. Grouping several units may improve scheduling efficiency, but unaffected units do not automatically require replacement.
What measurement should I provide online?
Use an approximate visible-glass or sash size for planning and clearly label how it was measured. Do not use homeowner dimensions to order the final unit.
Start with what you know
See whether your foggy window is a glass-only project.
Choose Window Glass, select foggy or failed sealed unit, and add the number of openings, approximate sizes and photos you have.