Condensate in Double Glazed Windows

Condensate in Double Glazed Windows

Eliminating fogging and condensate which has accumulated in a double pane window, in the hope of restoring it to its thermal efficiency is impossible. Affected windows cannot be restored to the original condition and level of performance which they attained before the condensate entered. At the moment there are two ways to partially remedy the damage caused by the condensate. You can either replace the glass unit section of the window, or drill holes in the outside pane, and clean the condensate off from the inside of the unit before installing’ one way air vents to help prevent further condensate accumulating. If the condensate problems have arisen on a glass sliding door the only alternative is to replace it.

moisture between panes

moisture between panes

The same applies with any tempered glass window. Tempered glass breaks when drilled. Condensate accumulates in double pane, thermal or insulated windows because the windows units are constructed from two panels of glass, in a ‘sandwich like’ set up placed over a sealer and spacer. The condensate accumulates between the two panes. The space is filled with one of a number of types of gas, usually krypton or argon. The sealed space provides a thermal gap which allows the window to perform its functionbut also provides the opportunity for condensate to form. Sometimes the spacer will contain a desiccant substance which can absorb the moisture in the air present between the two panes, but condensate can nevertheless still form. Condensate present in a thermal window usually suggests that the seal between the panes of glass has failed, possibly combined with the desiccant having become saturated, leaving it unable to absorb the condensate.

The failed seal permits water vapour and air to penetrate into the window space leaving nature itself to do the rest, and condensate forms. Evidence of condensate is a guarantee that that the gas which you expected to be present between the panes has escaped. But unfortunately there’s no going back. You can’t reseal an insulated window. To eliminate the condensate and restore the unit’s thermal performance, you need to replace the glass. Most glazing units affected by condensate can be replaced, so you should be able to avoid the cost of replacing the whole window frame. If the window is still covered by its warranty you should contact the supplier. You might even receive a free replacement. But if don’t receive any joy from the supplier contact the manufacturer. Even if the warranty has run out when you first notice the condensate, its still a good idea to at least contact the manufacturer. You should receive some advice, and you might get a better deal on options for replacement. Some local glass companies can manufacture a replacement window unit to any size.

Removing Condensate from an existing Unit

You might see some adverts from companies offering to ‘restore’ condensate affected windows, back to their original thermal performance. These claims can be unreliable and you may find yourself wasting money on what in the end will be an ineffective long term solution. The alternative to replacing the unit is to remove condensate from the window by taking out the moist air from between the panes and replacing it with dry air. Thermal window ‘restoration services’ come to your home and drill small holes in the corner of the window unit affected by condensate. They spray liquids into the inside surfaces of the panes through one of the holes and suck them out through the other. Once the window is cleaned and dried and (theoretically) free of the condensate, the holes are sealed with vent plugs which allow water vapour and air to escape but not re-enter the unit to cause more condensate. Whether this process, will be a solution to your own condensate problem, is however something of a lottery. Users of the service give conflicting accounts of its success (or otherwise) in resolving their condensate issues. The service typically costs up to half that of a replacement window but the question is, are those odds worth the risk. You know for certain that replacement window units will be free of condensate but unfortunately you won’t necessarily know for several months if the restoration service has worked. If it hasn’t it will have been a waste of money. So don’t even entertain using this type of service unless you receive a full money back guarantee which will be honored without quibble if your condensate returns. Consider the options carefully. On the one hand the restoration route doesn’t damage your window because once condensate has entered it, the window is already past its shelf life. But if the company doesn’t cooperate in giving your money back, or at least have another go at permanently freeing  the unit of condensate you’ll have suffered a great deal of hassle and cost to no effect. If thermal performance, is the top priority it’s best to avoid restoration completely. The chances of thermal performance being reliably restored by restoration is negligible

Avoiding Condensate Developing

Even when your windows are functioning normally and no condensate is evident between the panes it’s a good idea to avoid aggravating the risk in the first place. You should take all necessary steps to avoid condensate forming in the home in general. We provide advice on dealing with condensate in general elsewhere. But owing to the sheer volume of water, the kitchen and bathroom in particular are far and away the worst sources of the vapours which enter between the window panes and can cause condensate problems throughout the house. Always turn on the extractor fans or leave windows open when cooking or showering, and for a while after you’ve finished. And when cooking always keep the lids on the pans. The water vapour which escapes from pans is hot that so contains large amounts of water available to spread and condensate, throughout the house When you consider how much water boils away from a large pan in a relatively short period of time you can envisage the amount of condensate available to be spread over the surfaces and corners of your windows units. There is still moisture present in the air after cooking and showering which settles as condensate when you’ve left the room. And if possible keep the bathroom and kitchen doors close to avoid moisture entering the rest of the house and settling as condensate on the windows elsewhere. If you’re drying clothes in the house, put them in a closed room with the windows open. And if you use a tumble dryer make sure that the machine vents to the outside. Hot vapour from a tumble dryer contains a considerable amount of water which remains in vapour form and can travel around the house and settle as condensate on all the windows. Keeping the kitchen and bathroom at a steady temperature can help avoid condensate. There’s a not unreasonable temptation to leave the kitchen and bathroom unheated when not in use, but it’s the drastic change in air temperature which allows vapour to condensate and saturate the windows frames