- Elevating Exteriors – From Concept to Completion
- Elevating Exteriors – From Concept to Completion
A hazy ring inside your double-pane glass usually isn't dirt, and no amount of window cleaner will fix it. When condensation or fog shows up between the panes rather than on the surface, it means the sealed glass unit itself has broken down. It's one of the most common window calls Alpine Exteriors fields from homeowners in Mount Vernon, Anacortes, Burlington, Sedro-Woolley, La Conner, Stanwood, Camano Island and Bellingham, and the fixes range from a simple glass swap to a full window replacement depending on what's actually failed.
The telltale sign is fog, haze, or streaking that sits inside the glass, between the two (or three) panes, and doesn't wipe away from either side. It often starts small, a cloudy arc in one corner, or a faint ring near the edge of the sash where the seal usually fails first, and spreads over months or years as more moist air works its way in. Some units develop a white, powdery mineral deposit on the inside of the glass once trapped moisture has evaporated and re-condensed repeatedly; that residue is a sign the seal has been gone for a while.
It's worth distinguishing this from two things that are not seal failures. Condensation on the inside surface of your windows on a cold morning is a humidity issue inside the house, not a broken window, it's common in our climate during the wetter months and is addressed with ventilation, not glass replacement. Condensation on the outside surface of the glass on a cold, clear morning is just dew forming as the glass drops below the outdoor dew point; it usually burns off within an hour and isn't a defect at all. Fog trapped between the panes, by contrast, doesn't clear no matter the weather.
Every insulated glass unit is built with a metal or composite spacer between the panes, packed with a desiccant and sealed with an adhesive edge seal. That seal is the whole system, once it fails, outside air and the moisture in it leaks into the gap, the desiccant saturates, and you get permanent fog. Seals wear out from age and use anywhere, but a few things about this part of Washington tend to shorten their working life or make failures show up faster.
Our winters bring long stretches of steady rain from roughly October through March, and on walls that catch the weather, south and west exposures especially, that water sits against sills, trim, and window flashing for days at a time. Repeated wetting and drying around the frame stresses the edge seal from the outside even before the seal itself gives out. Add the wind that comes off the Skagit flats and funnels down the Strait of Juan de Fuca, and a lot of homes here take rain almost horizontally against the glass during winter storms, which pushes water and pressure into every gap in a marginal seal.
On the islands and waterfront, Camano Island, La Conner, and the shoreline neighborhoods around Anacortes, salt-laden air speeds up corrosion of the metal spacer inside the unit, which is often the first thing to actually fail. Homes closer to the foothills toward Sedro-Woolley see occasional ice and snow in winter, and freeze-thaw cycling on a seal that's already marginal will finish it off faster than steady cold alone would. None of this is unique to any one town in the service area; it's a regional pattern, and it's why window seal failure shows up on a lot of homes here well before manufacturers' full advertised lifespans.
It's also worth noting that homes built or re-windowed to meet more recent Washington State Energy Code requirements often have argon-filled, low-E double-pane or triple-pane units. Argon gas improves insulating performance, but when the seal fails, the gas escapes along with the visible fogging, so newer, higher-performance windows aren't immune, they just show the failure the same way older units do.
Generally, no, foggy glass by itself isn't a safety issue and won't damage your home structurally. It's primarily a comfort and energy-performance problem: once the sealed gap between panes is compromised, the window loses much of its insulating value, and during our long, wet heating season that shows up as a colder spot in the room and a higher heating bill than a properly sealed window would produce.
Where it becomes more urgent is if the moisture isn't staying confined to the glass. Soft or discolored wood at the sill, paint bubbling on interior trim, or a musty smell around the window frame suggests water is getting into the frame itself, not just the sealed glass unit, that combination is worth addressing before the next round of winter rain rather than waiting. A single foggy pane on an otherwise sound window, though, is something you can plan around rather than treat as an emergency.
There are two honest paths once a seal has failed, and which one makes sense depends on the condition of the frame and sash, not just the glass.
Some companies offer a defog service, drilling a small hole into the unit, extracting the trapped moisture, and sealing the hole. It's the cheapest option, but it's worth understanding what it actually does: it clears the fog temporarily without repairing the underlying seal. Some homeowners get a year or two out of it; others see the haze return within months, especially on a unit that's taken a lot of wind-driven rain or salt exposure. We'll mention it as an option when asked, but we don't present it as a permanent fix, because it isn't one.
If the frame and sash are still sound, no rot, no warping, hardware still working, the more durable fix is usually a glass-only replacement: swapping in a new sealed glass unit while keeping your existing frame. It costs less than replacing the whole window and, done correctly, performs the same as new glass would.
Full window replacement makes more sense when the frame itself is failing, common on older aluminum-frame windows, when several units in the same house are fogging around the same time, a sign the whole batch is reaching end of life, or when you're already planning to upgrade to better-performing glass to meet current comfort or Washington State Energy Code targets. It costs more up front but resets everything at once, frame, hardware, and glass, rather than treating one symptom at a time.
| Option | Typical cost range per window | Best fit |
|---|---|---|
| Defog / moisture extraction | Low, roughly $100 to $300 | Budget stopgap; not a permanent fix |
| Glass unit replacement | Moderate, roughly $300 to $700 | Frame and sash still sound |
| Full window replacement | Higher, roughly $600 to $1,500 or more | Failing frame, multiple units failing, or planned upgrade |
These are general ranges, not a quote, actual pricing depends on window size, style, grille pattern, and access. We'll give you an exact number after a look at the specific window.
You can't stop a glass seal from aging, but you can slow down the things that shorten its life in this climate.
No, once the seal has failed, there's no way to clean the inside of the gap without disassembling the unit. Any haze that appears between the panes and doesn't wipe off from either surface means the seal is gone, and the only real fixes are a defog service, which is temporary, a new glass unit, or a full window replacement.
Yes, to some degree. A failed seal means the insulating air or argon gap between the panes has escaped, so that window is doing less work than a sealed one would, especially during our long heating season. It's rarely dramatic on a single window, but if several units around the house have failed at once, it adds up.
Usually not. Seal failure is considered normal wear and gradual deterioration in most policies, not sudden damage from a covered peril, so it's typically treated as a maintenance item you pay for out of pocket. It's worth checking your specific policy, but don't count on coverage.
There's no fixed number, it depends on the product, installation, and exposure, but we regionally see a fair number of seals start failing well before their full advertised lifespan, sooner on units exposed to a lot of wind-driven rain or salt air. Sheltered windows on the leeward side of a house often outlast ones facing the weather by years.
If you're seeing fog between the panes on one window or several, it's worth having someone look at the frame and sash, not just the glass, before deciding between a repair and a replacement. Alpine Exteriors serves Skagit, Island, and Whatcom counties, Mount Vernon, Anacortes, Burlington, Sedro-Woolley, La Conner, Stanwood, Camano Island, and Bellingham, and can walk your windows with you, tell you honestly which units are worth re-glazing and which have earned a full replacement, and put together a plan that fits your budget rather than pushing the most expensive option by default. Alpine Exteriors holds Washington contractor license ALPINI751OW; reach out for an assessment before the next round of winter rain sets in.
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