Today I had the window supplier for the house come and inspect some of the windows. I had noticed fog in the windows and I could not clean it off after wiping both sides of the window. After inspecting all the full size windows in the house we found that 8 of 8 top sections of windows had their seals broken. The thin tape/seal between the panes of glass had turned yellow and had begun to peel. He told me that was a sign the seal had broken. The bottom half of the window looked okay and those seals were still white. Luckily, the windows have 10 year warranties and replacement will be covered. Whew!
It will take 2 weeks for the new window panes to arrive and the installer will return to replace them. I think most windows carry a warrenty so it might be a good idea to check the seals between the panes from time to time.