While double-pane windows are the best ones that you could have from an energy standpoint, they do come with an issue that single-pane windows don’t have. You might be aware that there is a gas in between the glass panes to insulate better, but if there is a leak in the seal that keeps that gas in, you might notice that your windows turn a milky white color. Condensation on your windows will also prove to be more of a problem with the gas missing.
Unfortunately, this is a difficult issue to fix. The easiest way is to have the window replaced, but unfortunately, this is also the most costly solution.
There is a way to restore the window by drilling holes and re-sealing it, but this is not going to be a perfect fix, and the window will not be as good as it was from the factory. It is an option if you don’t want to spend the money on having the windows replaced.