What It Means When Your Home’s Windows Start Fogging Up

What It Means When Your Home’s Windows Start Fogging Up


Window fogging can occur for more than one reason. If you’re a homeowner, you may have noticed times when some or all of your home’s windows develop a fog that makes it hard or impossible to see outside. You may have tried to determine whether your foggy windows occur at a certain time of day or during a particular weather event such as a heavy rain or extreme heat. In reality, there are several different reasons why you may be experiencing window fog.

Exterior and Interior Temperature Differences

Window fog sometimes occurs when the temperatures inside and outside are sufficiently different. The temperature difference causes condensation, which creates foggy windows. The simplest remedy for this problem is to adjust your indoor temperature to a level closer to the temperature outside. In the summer, this would mean raising your thermostat temperature a few degrees, while in winter a downward adjustment to your thermostat would be needed. This may fix your problem. 

Excess Humidity Inside Your Home

If the air inside your home is significantly more humid than the air outside, window fogging can result. Reducing interior humidity usually requires determining the cause of the humid conditions. Humidity can result from a variety of factors, including hidden mold, inadequate roof or attic venting, or excessive ground moisture near your home. While you may be able to lessen the problem by purchasing a dehumidifier for in-home use, periodic window fogging may continue until you find and fix the root cause of your home’s humidity. An inexpensive instrument known as a hygrometer can be purchased to check your home’s humidity level. If you aren’t sure whether your fogging is humidity-related, or you can’t determine the reason that your home is excessively humid, the best move is to contact a qualified home contractor to root out and correct the problem. 

Broken Window Seals

Failing seals around windows are a major reason for window fogging. Window seals often fail due to age-related deterioration. If your home is more than ten years old, you may be experiencing age-related failures, in which case the best remedy is to install new, double-paned windows. 

If your home is still relatively new, you may have a defective window seal. Most newer homes are constructed with double-paned windows. These windows have a small space between the interior and exterior panes, which is designed to retain heat in winter and cool air during the summer. Occasionally, material failure causes a seal around either the outer or inner pane to break. Since the windows are double-paned, the seal around one pane may fail before the seal around the other. If the interior pane fails but the exterior pane remains sealed, you may not experience condensation and realize you have a problem until both panes fail. Once that occurs, condensation can easily form between the panes, producing window fogging. At that point, window replacement is usually needed. Depending upon the age of your home, there may be a warranty that will offset some or all of the costs associated with window replacement.

So, What’s the Bottom Line?

Regardless of the reason for window fogging, the problem should be promptly identified and corrected. As we’ve noted, fogging can be a symptom of a larger issue such as mold, drainage issues, or inadequate home venting. Or, your fogging may simply be due to the failure of one or more window seals. 

Left untreated, window fogging can lead to more serious issues such as structural rotting or health problems for you and your family. If you have window fogging, the time to act is now. And, if your problem does require window replacement, there is good news on several fronts. 

First of all, newer, better insulated windows usually produce energy savings for the homeowner, which can be substantial depending on the number of windows replaced. Replacing older windows with modern, double-paned windows can generate annual heating and cooling cost savings of over 20%. Newer windows are also more secure. Lock failures on older windows are common, and often go unnoticed. 

So, if you’re experiencing window fogging, do the smart thing and contact us. We have the expertise, experience, and skill to identify and fix the problem once and for all. And, we’ll do it at a cost that won’t bust your budget. We want to be your home maintenance partner. Give us a call. You’ll be glad you did.