The standard in patio doors is two panes of glass, factory sealed around an insulating airspace. The frames may be aluminum or wood. The style may be French doors on hinges or sliding doors on tracks. But aside from a stray baseball, every double-glazed door is vulnerable to the same fatal flaw: fogging.Fog on the outside or inside surfaces is only an occasional nuisance you can wipe away. But you can't clear moisture between panes, although it may change some with the weather. On humid days, it might cloud the entire panel, then on dry days almost disappear. But it never goes away for good. The problem is cosmetic, doesn't hinder door operation, or in most cases even reduce its energy efficiency very much. But it makes the door look dingy, and sometimes the fog is so dense you can't see through it.It's a cracked gasket -- a breach in the rubbery edging installed at the factory to seal the dead airspace between panes. It might rupture after many years of normal operation, or from one crash closing.
It might crack because a broken wheel bounces the door along the track, or from temperature swings that expand and contract the gas sealed inside. (Most fog problems occur on the sunstruck side of the house, where temperature swings are greatest.) Whatever the cause, once the seal is broken the formerly dead airspace comes to life. When it's muggy outside, it's muggy inside the double glazing, too.The one sure fix is to replace the glass panel. The drawback is the expense -- unless replacement is covered by warranty. Depending on door size, type, and condition, replacement materials and labor could run $400 or more. That may be worthwhile if you're repairing one of several panels in a top-line, wood-frame unit that cost $3,000. It's an iffier proposition with an entry-level aluminum slider. Then it's like replacing the blown engine in a car. You could make the investment and gain a working version of the same old model, or put the repair money toward a new car.But some contractors advertise that they can fix this problem on site for less than the cost of replacement.
Sounds good, until you find out what their plan is. Sometimes, it's simply drilling holes that make the gasket leak everywhere. This lets out the moisture, they say -- and it certainly will on a dry day. But guess what comes back through all those holes the next time it rains: moisture.Others say they'll shoot a desiccant (absorptive drying agent) into the space between panes, which also means drilling more holes. That will help temporarily -- long enough for the contractor to collect his money. But as engineers at Pella, a leading manufacturer, put it, "Desiccant material will attract and hold as much moisture as it is capable of, but will eventually become saturated. When that happens, fogging will occur."De-fogging doors seems to attract contractors who promise what they can't deliver. No one can duplicate the elaborate vacuum and sealing processes of a door factory at your house. But some companies offer a kind of in-between fix. Their solution starts the same way: drill another hole, "so the unit can expel moisture on its own," the company says.
Then they add a small valve that opens when sunlight pressurizes the air between the panes, allowing moisture to escape. When the valve closes, "the sealed unit no longer accumulates moisture and has recovered its dry air insulating properties." To restore a typical fogged door, Apex charges $300 per panel.The California-based, Glass Guru Co. (the nearest of their 32 franchises is in Columbus, Ohio), has a similar approach. After drilling into the airspace, the company says they "clean it, flush it with a drying agent, and then reseal it with our patent-pending micro vents."With the vent approach, there are only two possibilities. The vent valve can open once to expel moisture and then close for good. Or it can keep working, opening and closing when fog builds up again. Apex says "the valve keeps working." That amounts to a breathing window, not a factory-sealed window. To explore this option, you need to be clear about exactly what the de-fogging service is promising: no more fog and a warranty to remove it at no cost in case there is?
Or some fog now and then as the vents open and close. New Owner Demolishes O.j. Simpson MansionDark meaning of bubble-gum Pumped Up Kicks is tough to chewHandshakes For All, Including Simpson, As Fung Ends Testimony Pain relievers: What are the differences?Nicole Simpson's Grisly Death Described To Jury10 reasons why you want the jobExcessive humidity can also result in water leaks. When heavy fog accumulates on your sliding glass doors, it is probably due to your home's high humidity levels. Fog on any glass surface is due to condensation, which occurs when the heated air from your home meets the cold air on your door surface. This can result in numerous homeowner issues, such as damage from ice formation. Eliminate fog on sliding glass door windows by taking measures to dry out your home's air, which also helps resolve mold and mildew buildup problems. However, keep in mind that air in the home that is too dry can result in overly dry skin and dry mucus membranes, which can lead to nosebleeds and other health problems.
Dehumidifier Use a dehumidifier to maintain fog-free sliding glass doors. Dehumidifiers remove moisture from the air in whatever room they are placed in. Close off other doorways if possible so the appliance won't have to work as hard. Dehumidifiers work best to dry out a room and therefore remove sliding door condensation when humidity levels are above 50 percent. When humidity levels are below this, such as in the wintertime, you probably have to employ other methods to remove condensation. Eliminate Leaks Inspect around the doors and the doors themselves for cracks and insufficient seals that can cause cold air to seep through and result in door condensation. Use the appropriate sealants and caulks to repair either or both of these issues. When the damage is too severe, the window glazing might require replacing. Drapes Adjust your glass door's drapes if applicable before you retire for the night as condensation can occur on windows behind draperies, resulting in foggy sliding doors the following morning.
Keeping drapes open throughout the night can eliminate this issue. You can also use sheer, lightweight drapery options to reduce moisture on doors. Removing Other Sources Of Humidity Remove additional humidity sources to eliminate fog on glass doors. This includes utilizing exhaust fans while cooking, washing and drying clothing, or bathing; make sure all exhaust fans are working properly and vent outdoors, as some apartment building or home fans may not operate as they should. Exhaust fans also generally require less energy to run than dehumidifiers, and also remove any pollutants and odors in the air. Check for other sources of dampness in the home, such as wet piles of laundry or containers of standing water leftover from floral displays. References North Dakota State University Extension: Window Condensation Common ProblemEnlighten: Preventing Condensation on WindowsU.S. Environmental Protection Agency: Controlling Moisture Photo Credits Thinkstock Images/Comstock/Getty Images Suggest a Correction