Fogging of dual pane windows in RVs is, unfortunately, a fact of life for many owners. Dual pane windows have been widely used in houses for decades and their energy savings are well documented, which is a major reason why they are also used in RVs. The air layer between the glass panes provides a huge increase in the insulation quality of the window and prevents condensation from forming inside as long as the window’s inner air seal is unbroken.
These windows work well in houses, but in RVs the movement of being on the road puts a lot of strain on the seals. Seal failure is the reason windows fog.
There are rubber (or other material) seals that close off the inner air pocket in the window and prevent humidity from penetrating the two panels of glass, which are sealed and dry when built at the factory. Once that seal is compromised, however, humidity is allowed to enter the air pocket of the window, resulting in condensation and fog.
Today, owners have several choices when it comes to restoring a clear view to their fogged dual pane windows. The easiest, but perhaps most expensive, is to simply buy and install new windows. You can do this on your own or take your RV to a service center and have them install a replacement window.
Another option is to have your windows removed and take them to a qualified glass/window shop and have them repair the windows. Some readers have reported good results with this method and it seems to be a reasonably priced option. Depending on the turnaround time, this also means that you need to have the RV covered while the windows are out.
As you search for a qualified shop, make sure to let them know they will be dealing with RV dual pane windows. Some shops simply will not or cannot make these kinds of repairs. We have also discovered that square or rectangular glass windows are a lot easier to work with than glass with rounded corners.
Some, but not all, of these windows are factory filled with argon or nitrogen, which is a dry gas ideal for occupying the space between the panes of glass. If you can find a facility that has the capability of refilling the space with a dry gas, your chances of success are a lot better because it is the moisture inside the cavity that causes the condensation. We have talked with some RVers who have performed their own DIY repair and they simply drilled a small hole in the window frame and used welding argon gas to inject inside the window cavity, then resealed the hole with silicone sealant.
There are RV-specific repair facilities that can do this work for you. In most cases, you bring your rig to the facility, they remove the windows one at a time and disassemble them completely. They then clean the glass to remove the fogging and reassemble the glass with completely new seals. They also use better materials in hopes of preventing this from recurring.
In some cases, the interior glass is etched beyond the point of normal cleaning or polishing and must be replaced. To try to prevent this, when you see fogging on your windows you should have them repaired soon rather than waiting months or years. The longer you wait the more difficult it is to remove the deposits.
Some of these companies also offer the option of shipping your windows to them for this repair service, so you perform the removal and reinstallation.
In several of these options, owners who are fairly handy can save money by doing their own removal and reinstallation. See below for our basic how-to on removing and reinstalling a window.
Depending on the size of the window, you may need two or three people to ensure the window can be safely removed and reinstalled from a ladder without risk to those performing the work. The window we replaced was fairly small and only required two people to completely remove it and install a new one.
You will need some basic tools such as a ladder, outdoor-rated clear sealant, a plastic scraper (to remove the old sealant) and a rubber mallet (just in case). You will also need to obtain the same type of gasket or butyl rubber sealing tape originally used by your RV manufacturer to seal the window. We installed a new window and it came with a new rubber self-adhesive gasket.
Of course, every RV manufacturer uses slightly different methods and parts so your process may vary slightly from the one shown here. Even if your method is slightly different, this offers you enough information to do the work yourself and save a lot of money in the process. If you prefer not to try this approach, we have included a list of companies that will do all the work for you. Some attend RV rallies, so check their schedule and you could save on driving, too.
For More Information
Dave Root RV Glass Repair (541) 280-3612, www.daverootrvglassrepair.com
Duncan Systems Inc. (800) 551-9149, www.duncansys.com
RV Fog Dr. (501) 278-3015, www.rvfogdr.com
RV Glass Solutions (888) 777-6778, www.rvglassexperts.com
Suncoast Designers Inc. (727) 868-2773, Suncoastdesigners.ccwindow.com.