Foggy Double-Pane Windows - Repair vs Replace

Foggy or cloudy double-pane windows are a clear sign that the sealed insulating glass unit (IGU) has failed. Moisture has gotten between the panes and cannot be wiped away. The good news: you usually do not need to replace the entire window. Replacing just the glass unit restores clarity and efficiency at a fraction of the cost.

Why Do Double-Pane Windows Get Foggy?

Double-pane windows have two layers of glass with a sealed air or gas space between them. A perimeter seal keeps that space dry and often filled with argon gas. When the seal fails—due to age, temperature stress, or manufacturing defect—moisture enters the space. That moisture condenses on the glass, causing the fog or haze you see. The condition is permanent; the only fix is to replace the IGU.

Repair (IGU Replacement) vs Full Window Replacement

In most cases, the frame and sash are still in good shape. Replacing only the glass unit—the IGU—preserves the frame, trim, and look of your window while restoring clarity and insulation. IGU-only replacement typically costs 60 to 80 percent less than a full window replacement and can often be completed in under an hour per window. Full replacement is only necessary when the frame is damaged, rotted, or you want a different style or material.

What to Expect When You Replace the Glass Unit

OhMyGlass measures the opening on-site, orders or fabricates the correct sealed unit (including Low-E and argon options for better energy performance), and installs it with minimal disruption. We serve Toronto and the GTA with free quotes and same-day or next-day service when possible. Get a free quote for foggy window repair or IGU replacement today.