Things You'll Need
Double-panes are a common feature used to increase the energy efficiency of windows. In double panes, two panes are separated by a sealed pocket of inert gas. This gas serves as an insulator, slowing the rate at which heat can enter or leave through the window, and helping keep the house cool in summer and warm in winter. As double-pane windows age, however, small leaks can develop in the seal. These leaks can let in moisture, which can form condensation when the temperature drops.
Remove the window from the casement, and place it on a soft tablecloth or other soft surface.
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Carefully press a utility knife through the sealant directly next to one of the window panes. This will make a hole in the sealant, allowing you to cut through and separate the panes.
Pull the knife out. Press a hacksaw blade into the slit you just cut with the knife. Gently saw back and forth to cut through the sealant all the way around the window. Remove the pane, and place it on the tablecloth.
Scrape excess sealant off the exposed edge of the spacer with a putty knife. Then, scrape the edge of the pane you removed in Step 3 to break off the sealant. Go slowly and carefully to avoid damaging the pane.
Mix 1 cup water with 1 cup of rubbing alcohol and 1 tablespoon of vinegar in a bowl to make a cleaning mixture.
Vacuum the inside of the pane attached to the spacer to remove any debris. Dip a clean rag in the cleaning mixture, and wipe the inside of the window attached to the spacer.
Wipe the side of the second pane that was adjacent to the spacer with the cleaning mixture. Dry both windows with a clean cloth. Use a blow dryer on both panes to remove any residual moisture.
Put a package of silicone desiccant in the windowpane with the attached spacer near the bottom corner. The desiccant will absorb moisture trapped in the air, preventing the window pane from fogging up on cold days. Put the package of desiccant in the bottom corner of the window so it is not visible when you put the window back in its frame.
Run clear silicone along the top of the spacer in a thin bead, making sure to cover the entire spacer. Carefully position the pane of glass you removed, and press it down on top of the spacer with your fingertips.
Run a second bead of silicone along the edge where the pane joins the spacer to reinforce the connection.