Foggy Insulated Glass (IGU) Replacement

Fog, haze or streaks between the panes mean an insulated glass unit has failed. We replace foggy units in storefronts, windows and curtain wall, usually without replacing the frames.

Why insulated glass fogs

An insulated glass unit is two or three panes separated by a spacer and sealed around the edge, with dry air or argon gas in between. Over time, sun, heat, movement and water standing in the frame break down the edge seal. Moist air gets in, condenses on the inside of the glass and leaves mineral streaks. Once a unit fogs, it has failed: the insulating gas has escaped and the unit no longer performs as designed.

Replacement versus defogging

Some services offer to drill and defog failed units. That can improve appearance temporarily but does not restore the seal or the insulating gas, and the fog often returns. Replacing the unit restores the appearance and performance and usually comes with a manufacturer warranty.

Matching the new unit

Overall thickness to fit the existing glazing pocket
Outer and inner glass thickness and type, including tempered where required
Tint and low-E coating to match neighboring units
Spacer color and gas fill
Altitude allowance for buildings at high elevation

Why units keep failing

If units fail repeatedly in the same frame, water is often sitting in the glazing pocket because the weeps are blocked or the setting blocks are missing. Insulated glass edges cannot sit in water. When we replace a unit, we clean the pocket, check the weeps and set the unit on proper setting blocks so the new one lasts.