How to Repair Double Pane Windows

Many homeowners are choosing double-pane windows when building or remodeling their homes. These windows protect against energy loss and can help to lower utility bills. Double-pane windows are two panes of glass that are held ½ to ¾ inch apart by spacers. Between these two panes of glass is a layer of air that prevents the transfer of heat that normally occurs when the temperature inside and outside the glass differs. Because of their construction, however, double-pane windows can be more complicated to repair than single-pane windows.

Occasionally, homeowners may need to repair their double-pane windows.

Step 1

Remove the window from the frame as recommended by your owner’s manual. The window assembly may be held together with screws that must be removed before the seal can be lifted.

Step 2

Set the window on a flat surface and use a screwdriver or other flat-edged tool to remove the butyl seal to separate the two panes of glass.

Step 3

Remove the broken pieces of glass from the frame carefully.

Step 4

Clean the remaining pane with a solution of isopropyl alcohol, vinegar and water to remove dirt and grease.

Step 5

Clean the new glass with the same solution to ensure that no dirt or oil is trapped on the inside of the window between the two panes.

Step 6

Set the new pane of glass on top of the spacers that separate the glass panes, adjusting the pane to sit squarely on the spacers.

Step 7

Apply a silicone sealer around the perimeter of the spacer, leaving no gaps between the spacer and the glass.

Step 8

Run a thick seam of silicone around the entire perimeter of the glass, ensuring that the spacers are covered as well.

Step 9

Let the silicone cure for at least 24 hours before replacing the window in the frame. The amount of time recommended for curing may vary depending on the product you use. Follow label directions carefully.


  • Repairing one pane of a double-pane window can easily stress and break the other glass pane. Place the window on a well-padded surface when attempting to replace the glass.
  • Wear gloves when working with broken glass and to help prevent fingerprints on the inside of the glass panes.
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