Water Marks Between Glass Pane

The crystals inside the spacer bar have broke down or the gas in the bar has it’s an easy fix just replace the glass with up to date bars

Unfortunately the rubber seals joining the two pains has broken down letting in moisture causing water stains Again unfortunately it will require a new unit of two new pains sealed together

Failed unit... replace glass unit only! .. not frame!

Hi, yes you will need to replace the glass, the sealed units are no longer sealed and will not be as energy efficient anymore or soundproof, the longer you leave it the worse it will get, any window fitting company or handyman should be able to replace them for you, maybe check how old they are aswell as most companies do a 10year guarantee on the glass so you may still be covered

After time the seals in double glazed units can break down. It's very common in older units. A local window company should be able to measure up for you and provide you with a quotation for replacement of the unit (you don't need to replace the whole window)

Sounds like your double glazed seal between the panes has failed. The only fix is to replace the glazing. It would also be worth checking the style of glass. Many slimline double glazing products have this problem when in large panes. Glass does expand and contract, and does flex too. In hot conditions it is not unusual for the panes to expand and bevel inwards to touch in the middle. When this happens it looks like a circle appears in the center, and can distort your view. Over time this breaks down the seals and eventually they begin to 'fog'.