Have you noticed cloudy patches, streaks or droplets between the panes of your office or storefront windows? That is not something cleaning can fix. It is a sign that the insulated glass unit (IGU) has failed.
What is an insulated glass unit?
Most modern commercial windows, storefronts and curtain walls use IGUs: two (or three) panes of glass separated by a spacer and sealed around the edges. The sealed space is filled with dry air or argon gas, and one pane often carries a low-E coating that reflects heat.
Why do commercial windows fog up?
- Seal failure with age: perimeter sealants slowly degrade under UV exposure and temperature cycles.
- Thermal stress: large expanses of glass on sunny elevations expand and contract every day.
- Water sitting in the frame: blocked weep holes or failed gaskets leave the edge of the unit wet, attacking the seal.
- Installation issues: units set without proper setting blocks or with incompatible sealants fail earlier.
Once moisture enters, the desiccant in the spacer becomes saturated and condensation appears whenever the temperature changes.
Why it matters
- The unit loses most of its insulating value, increasing heating and cooling costs.
- Views and natural light are reduced, and the building looks poorly maintained.
- Mineral deposits can permanently etch the inner glass surfaces.
Can foggy glass be repaired?
Some services drill and “defog” units, but the seal remains broken and the insulating gas is gone. The reliable fix is to replace the insulated glass unit. In most cases the existing frame stays in place: we measure the opening, fabricate a new unit and reglaze it with new gaskets or glazing tape.
An opportunity to upgrade
Replacing a failed unit is the perfect time to improve performance: switch to a better low-E coating, add tint to reduce glare, or specify laminated glass for security and sound control.
Planning replacement in an occupied building
For property managers with many failed units, we survey the building, map every affected opening and schedule replacement by floor or tenant so the building stays open. Each opening is typically completed in one visit once the new units arrive. Read our maintenance checklist for property managers to catch failures early.
Need help with your commercial glass?
CBE Glass serves businesses, property managers and general contractors across Washington DC, Maryland and Northern Virginia. Call (202) 492-0676 (24/7 for emergencies), email bid@cbeglass.com or request a free estimate.
