double pane windows

We've recently purchased a home that is approximately 22 yrs. old. All of the windows in the house have what looks like mildew stains on the inside of the glass. Is there a way to clean them without replacing them?

 

If these stains are between the panes of glass, your only fix is to replace the IG units (the glass). Call a glass shop and have them come measure and order them for you. They are a made-to-order item, and should take about 2 weeks to get. And since you are looking at going this far with the windows, you would better off to get these IG units with low-e glass. They will cost 15% to 20% more, but should reduce your utility bills by 10% to 20%. The other alternative would be to retrofit the windows. It would cost more, but, with the low-e glass, would give you a bigger savings on your utility bills. You may be able to go back on the seller for at least part of the cost, but this would not qualify as a hidden defect. The glass is right there in plain sight. It is really something you should have seen before purchasing the house.