Foggy Double Pane Windows in Kelowna: Repair or Replace, and What It Costs
A foggy window is a very specific failure, and the good news is that it is usually much cheaper to fix than homeowners assume. The haze between the panes does not mean the window is finished. In most cases it means one component of the window has failed, and that component can often be replaced on its own for a fraction of the cost of a new window. This guide explains what has actually happened and what each option costs in Kelowna in 2026.
What is actually going on
A double pane window is really two windows. There is the sealed unit, sometimes called the insulated glass unit or IGU, which is two panes of glass separated by a spacer bar and sealed around the perimeter, with dry air or argon gas in the cavity. Then there is the frame and sash, the vinyl, aluminum, wood or fibreglass assembly that holds the sealed unit and mounts into your wall.
When a window fogs, the perimeter seal on the sealed unit has failed. Moist outside air gets into the cavity, the desiccant in the spacer bar eventually saturates, and moisture condenses between the panes where you cannot clean it. Over time you get permanent mineral staining on the inner glass surfaces.
Two things follow from this. First, the frame is usually fine. Seal failure is a failure of the glass unit, not the window. Second, you have lost some insulating performance because the argon has escaped, though not nearly as much as people assume. The main cost of a foggy window is that you cannot see out of it properly.
Why Kelowna windows fail this way
Seal failure is driven by thermal cycling, and the Okanagan delivers a lot of it. A south or west facing window here can go from below freezing on a January night to well above freezing in direct winter sun, and in July it can sit at 60 degrees plus on the glass surface in the afternoon and drop 30 degrees overnight. The sealant expands and contracts through every one of those cycles.
This is why the pattern is so predictable in Kelowna homes: the south and west elevations fog first, often years before the north side, and windows with dark exterior frames or a large unshaded exposure fog earliest.
Most double pane units have a service life in the range of fifteen to twenty five years. If your home was built in the late 1990s or early 2000s, you are in exactly the window where this starts happening, and typically several units fail within a few years of each other.
Kelowna pricing in 2026
Sealed unit replacement, standard size, roughly 3 x 4 feet: roughly $300 to $550 per unit installed. The old glass unit comes out of the existing sash, a new one is made to measure and installed. Frame stays.
Sealed unit replacement, large or specialty: roughly $550 to $1,400. Large picture windows, triple pane units, tempered glass where required by code near a door or a floor, obscure glass, and units with internal blinds all cost more.
Sealed unit with low emissivity coating and argon fill: typically a modest premium over plain glass and worth taking. Low E is the coating that actually does the work on solar heat gain, and on a west facing Kelowna window it makes a real difference to comfort.
Full window replacement, retrofit or insert, standard size: roughly $900 to $1,800 per window installed. The existing frame stays in the wall and a new window is fitted inside it.
Full window replacement, full frame: roughly $1,400 to $3,000 per window installed. Everything comes out to the rough opening, including the frame, and new flashing and finishing go in.
Whole home window replacement, 15 to 25 windows: commonly $25,000 to $65,000.
The arithmetic is usually straightforward. If three windows in your house are foggy and the frames are sound, replacing three sealed units at $300 to $550 each is roughly $900 to $1,650. Replacing three whole windows is $2,700 to $9,000. That is why the sealed unit question is worth asking first.
When to replace just the glass, and when to replace the window
Replace just the sealed unit when:
- The frame and sash are in good condition, operate properly and lock properly.
- The window is not very old, or is old but sound.
- Only one or a few units have fogged.
- You are happy with the window style and how it opens.
Replace the whole window when:
- The frame is rotted, cracked, warped or has failed corners. Wood frames from the 1980s and early 1990s are the common case here.
- The window does not operate or seal properly, or you feel draughts around it even when closed.
- The sash has failed rather than the glass.
- You want to change the window style, for example converting a fixed pane to an operable casement for ventilation.
- You are doing an exterior renovation anyway, in which case the incremental cost of full frame replacement while the siding or stucco is open is much lower.
- Most or all of the windows in the house are at end of life. At that point per unit sealed glass replacement stops being good value.
There is a middle case worth mentioning. If your frames are sound but the windows are single pane, sealed unit replacement is not an option and full window replacement is the only path.
What about the defogging services you see advertised?
You will occasionally see a service that drills small holes in the glass, cleans the cavity and installs a breather vent. It removes the visible fog and it is cheaper than replacement.
Be clear about what it does and does not do. It restores visibility. It does not restore the seal, it does not restore the argon fill, and it leaves the cavity permanently vented to outside air, so the unit is functionally closer to two single panes than to an insulated unit. Mineral etching already on the glass does not come off. For a rarely used window in a garage or a shed it can be a reasonable economy. For a main living space window you look through daily, replacing the sealed unit is the better spend.
What to ask for a quote
- Measure carefully or have it measured. Sealed units are made to order and are not returnable. Measure the glass, not the opening, and note the thickness of the unit.
- Ask about tempered glass requirements. Glass in and near doors, at low sill heights and in bathrooms often has to be tempered by code, which costs more and takes longer.
- Ask about lead time. Sealed units are typically two to four weeks. Full windows are typically four to ten weeks.
- Ask about Low E and argon, and which Low E coating suits the orientation of that window.
- Ask about the warranty, which is usually separate for the glass unit and the labour.
- Get the disposal of the old glass confirmed.
Frequently asked questions
How long does the work take?
Sealed unit replacement is typically 30 to 60 minutes per window once the glass has arrived. A full window replacement is one to three hours per window.
Does a foggy window cost me much in heating?
Less than you would think. Losing the argon fill reduces performance somewhat, but the window is still double glazed. The real problem is that you cannot see out of it.
Can it be repaired without replacing the glass?
Not properly. The seal cannot be restored once it has failed.
Will more of my windows fog?
Probably. Sealed units installed at the same time on the same elevation tend to fail within a few years of each other. If two have gone on your west side, expect others. Some homeowners choose to do that elevation in one visit to save on repeat service calls.
Is fogging covered by warranty?
Sometimes. Many manufacturers warrant sealed units against seal failure for a defined term, often ten to twenty years, and some are transferable to a new owner. If you know the window brand and roughly when the house was built, it costs nothing to check before you pay.
Getting a Kelowna quote
View Kelowna Window & Door Solutions on the Okanagan Trade Directory
Window & Door Project Solutions supplies and installs windows and doors for residential and commercial projects across the Okanagan, with a dedicated Kelowna service page. Its window range covers vinyl, aluminum, aluminum clad, wood, casement, awning, sliding, bay, picture and replacement windows, plus commercial windows. On the door side it offers entry and front doors, French doors, sliding and patio doors and bifold doors, along with glass and both vinyl and fibre cement siding. With teams that have been installing windows and glass for many decades, the company backs its work with a manufacturer's lifetime window warranty and a 15 year labour warranty, and offers free in home consultations and estimates.