Remember that Argon gas that escaped? It was keeping your home warm in winter and cool in summer. With air (and moisture) in the cavity, the window’s insulation value drops by up to 50%. You are now heating and cooling the outdoors through that one pane.
Don't let the fog trick you—clear it up with a repair, not a band-aid. Have you successfully repaired a foggy window, or did you live with it until replacement? Let me know in the comments below! broken seal on double pane window
If left for years, the moisture reacts with the glass and hard water minerals. Eventually, the fog turns into hard white streaks that look like scratches. At that point, cleaning is impossible, and the glass must be replaced. Can you fix it? (Spoiler: Don’t drill the glass) If you search YouTube, you will find "hacks" for fixing a broken seal—drilling a tiny hole in the glass to let the moisture out and inserting a one-way valve. Remember that Argon gas that escaped
Call a local glass shop to quote an IGU replacement. If every window looks like a shower door: Get quotes for full replacement. You are now heating and cooling the outdoors
You wake up on a chilly morning, look out your living room window, and see it: a thick layer of fog trapped between the two panes of glass. You wipe the inside. Nothing. You scrub the outside. Nothing.