What can be done about foggy insulated glass units?

Many homeowners these days are choosing to install double or triple-paned insulated glass windows, also known as IGUs due to their increased energy efficiency. Because of their multiple layers that are often filled with inert gas and covered in special coatings, these types of windows are also referred to as thermal windows because they are able to retain over twice as much heat as normal, single-paned windows.

What are IGUs?

Virtually all windows these days feature an insulated glass unit or IGU. An IGU means that the window contains either two or three panes of glass, sealed together to form one solid pane for your window. While you may see single-paned windows in older homes, they are rarely used nowadays as IGUs are significantly more effective when it comes to saving energy.

There are a few different kinds of IGUs, and they vary based on what is used to fill the space between each of the panels. The cheapest and most basic version uses normal air between the panes. While this does offer more energy efficiency than a single pane window, air molecules easily react to heat and therefore do not do the best job creating a thermal barrier.

Alternatively, IGUs can also be filled with other types of gases. The best type of gas to fill the spaces between the panes are heavy, inert gases such as krypton or argon. Because the molecules in these gases move very slowly, it takes them a long time to be impacted by thermal energy. Therefore, they provide a strong thermal barrier for your windows, insulating them against heat loss.

What is the cause of foggy IGUs?

Over time, the seal around the edge of the glass in an IGU can begin to fail or break down. This allows the inert gas to slowly start to leak out as it is replaced by outside air. This outside air will most likely have moisture in it, which can condense between the glass panels under certain conditions. This may appear as a fogginess or haze on your windows. 

The fogginess caused by the condensation will come and go based on the temperature and weather conditions. It is usually the most noticeable during the fall and winter months as cool air outside causes the trapped moisture to condense.

Unfortunately, the seals on virtually all IGUs will fail at some point and cause the inert gases to begin leaking. There are some things that will negatively impact their lifetime, including temperature, sunlight, wind, and water, but many of these are unavoidable. You can expect your IGUs to have a lifetime of 15 to 20 years, at most, with proper maintenance. After this, they will lose their effectiveness and you can expect to notice some fogginess, no matter how good of quality they are. 

How can you fix foggy IGUs?

Previously, there was not a good way to fix foggy insulated glass units. You either had to replace them or just learn to live with them. Replacement of IGUs can be expensive if it requires replacing the entire window frame, but it is possible to retrofit IGU panels to existing window frames.

Recently, a new technique has been gaining popularity when dealing with foggy IGUs, called defogging. While this method does not actually repair your windows, it can reduce the cosmetic effects caused by condensation between the panes.

To defog a window, a trained technician drills a few small holes in your window to remove the moisture from between the panes. An anti-fog agent is added to the inside of the window, and then the holes are resealed. The goal is the remove as much water from inside the panes as possible and then quickly reseal it to prevent any more from entering.

Call Cypress Door and Glass Today!

If you’re having trouble with foggy windows, give us a call and we’ll check it out. We specialize in all glass products so we’re happy to provide you with some options!

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