Why windows fog up between the panes

What the fog actually is

A double-pane window is two lites of glass with a sealed, usually argon-filled gap. The perimeter seal and spacer keep that cavity dry. When the seal fails, moist air gets in. On a cold Metro Vancouver morning it condenses on the inner faces — the side you cannot reach with a cloth.

That is why wiping does nothing. The water is inside a sealed sandwich. Defog kits and “drill and dry” tricks do not restore the argon or the Low-E performance. The honest repair is to replace the unit.

How to tell it is the seal, not the room

• Condensation you cannot wipe from either side of the glass
• A haze that stays on dry days
• White mineral etching on the inner surface
• Visible droplets in the cavity on warm days
• A window that used to hold heat and now feels cold at the glass

Fog on the room side that wipes off is indoor humidity — showers, cooking, a dryer. That is not a glazing job. If you are unsure, send a photo. We will say which it is.

What it costs to fix — without a fake number

Sealed unit replacement is priced by size, glass spec (Low-E, argon, thickness), how many units, and access — ladder versus a third-storey patio. It is almost always less than a new window because the frame, trim, and sills stay.

A new window is the right spend when the frame is rotten, out of square, or the hardware is finished. If the vinyl or wood is sound, you are paying for glass, not a replacement opening.

Most Metro Vancouver homes can be quoted from a photograph and two measurements the same day. We do not publish a menu price because a 16×24 basement hopper and a 5×8 picture window are not the same job.

What we do

We measure the existing IGU, match thickness and spacer, fabricate a unit for this climate, and swap only the glass. Frames stay. Old glass is taken away.