In the colder months of the year, you might notice a lot more condensation on your windows than usual, but what if that condensation shows up in between the panes of your double-pane windows? This can happen in some cases when the insulation around the window has failed. There is a gap in between the panes in your windows, and this is what insulates them. What happens is that over time, the constant expansion and contraction of the gas between the panes when it is heated by the sun will wear out the seal and it will start leaking.
The problem is not only that you will have a film in between the windows that make it hard to see out, but you will also have a much less efficient home, causing it to cost more to heat and cool your home. There is no great fix for this problem since you can’t get the windows back to the same efficiency they had when they were manufactured, so replacing them would be the best option, albeit not the cheapest.