Condensation when it forms on double glazing, tends to form in ONE of three places. Either, 1) on the inside of the inside glass pane, 2) in-between the two glass panes or 3) on the outside of the outside glass pane.
Double glazed sealed units have only broken down if moisture or “misting” appears in-between the two glass panes. Any slight moisture or misting means the unit needs replacing, as over time the amount of moisture and misting will increase, making the window look unsightly. More importantly, it is clearly no longer a “sealed unit”, so will not be performing the function of a modern sealed double glazed unit, which is to keep the cold out, energy generated by your heating system in and allow solar gain to be retained within the dwelling.
Condensation on the inside of double glazing means there is a ventilation problem within that particular room and/or property that needs addressing. Conversely, condensation on the exterior means the double glazed unit is performing exactly as it should and you will notice it disappear throughout the day as the sun rises. The latter tends to occur in late Autumn, and is not usually a phenomena that lasts for too long. Quite often a picture frame effect will be created by misted squares or rectangles on the glass, surrounded by a clear outer “glass frame”. Yes, it is strange that this is actually “proof” the double glazing is performing efficiently, but better to have damp forming outside your windows than inside your house!
For UK home owners with contemporary energy rated aluminium or UPVC double glazing, replacing broken down sealed units is simple and easy to do. Most double glazing suppliers and installers should provide you with a 10 year sealed unit guarantee, as replacing them is not inexpensive, so it is worth partnering with a local well established company in your region who provides this customer service as standard with no call out fees for the 1st 10 years.
Properties with very old fenestration systems or timber double glazing many find replacement more costly, especially if the units are secured in the frames with putty rather than wooden beads.
While replacing sealed units that have broken down is not that important during the warmer summer months, it is vital to have the work done prior to the onset of Winter, as broken sealed units are leaky expensive energy out from your home into the environment, making your heating system work harder than need be. Aesthetically failed sealed units can be very unsightly, so all in all they are worth replacing to make the windows and/or doors the defective sealed are in, once again become energy efficient.
Hazlemere Window Company provide a replacement sealed unit service for UPVC and aluminium double glazed systems, whether or not the products were purchased from them or not. They do give priority to their existing customers under guarantee as you would expect, so if you don’t mind waiting a few weeks they are happy to provide a no obligation quote to replace double glazed sealed units. Find out more the services offered by Hazlemere Windows Service Department