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Advanced RemodelingWashington · Since 1998

Remodel Answers · Doors & Windows · Weatherstripping & Drafts

Why are my windows foggy between the panes?

Short answer

Fog between the two panes of a sealed insulated window means the seal has failed and moisture is trapped inside. The glass unit (called an IGU) can be replaced without replacing the whole window frame — usually $150–$400 per unit. It won't fix itself and it won't get better.

DK
Founder · Licensed WA Contractor · 20+ years
(425) 600-7735

Why it happens in the PNW

Insulated glass units are two panes with a sealed gap (often argon-filled). PNW temperature swings and prolonged wet weather stress the perimeter seal. Once compromised, humid outdoor air enters, warm indoor air hits cold glass, and moisture condenses inside where you can't wipe it off.

What to replace

In most vinyl and aluminum windows, just the IGU comes out. A local glass shop measures, orders, and installs. You keep the frame, sash, and hardware. Cost is 40–60% of a whole-window replacement.

When to replace the window

If the frame itself is rotted (common on 25+ year old wood-clad windows in Edmonds, Ballard, Mukilteo), if the hardware is failing, or if you're already going to be repainting the exterior — replace the window. Otherwise, just the glass.

What we see on Free Onsite Consultations

71%of homes assessed

Roughly 71% of homes older than 8 years show one or more failed caulk joints letting water into wall assemblies.

Caught early on assessment: $220–$750 · Left until failure: $1,200–$8,500

Based on real experience across the greater PNW, doors & windows issues like this are among the ones homeowners most often miss until they become expensive. Our Free Onsite Consultation catches them early — while they're still a maintenance item, not a repair.

How the Free Onsite Consultation works

Services we'd bring to this job

Especially common in these neighborhoods

We see this often on assessments across these the greater PNW cities we serve.

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