Double-Pane Window

A double-pane window (also called a dual-pane or insulated glass unit) consists of two layers of glass sealed together with a spacer bar along the edges. The cavity between the panes is filled with air or an inert gas—typically argon or krypton—which dramatically reduces heat transfer between the inside and outside of your home.

How Double-Pane Windows Work

The principle is simple: still gas conducts heat far less efficiently than a solid material or moving air. The sealed cavity acts as a thermal buffer, keeping warm air inside during Ohio winters and blocking summer heat from entering. The spacer bar around the perimeter contains a desiccant that absorbs any residual moisture inside the cavity.

Common Problems

When the hermetic seal between the two panes fails, outside air—and moisture—enters the cavity. This causes the characteristic fogging or condensation between the panes that cannot be wiped away. At that point, the insulating gas has escaped and the window’s thermal performance drops significantly.

Repair vs. Replacement

A broken seal doesn’t always mean the entire window needs replacing. In most cases, a window glass repair specialist can replace just the insulated glass unit (IGU), keeping the existing frame and sash. This is significantly cheaper than full-window replacement.