Is Condensation Between Window Panes a Problem?

Condensation is a natural reaction to contrasting temperatures, and if you can easily wipe it off your windows or doors, then you're well on your way to dealing with the problem. But if excessive moisture creeps its way in between the glass panes of your windows, then you may have a real problem on your hands. In this post, we're answering the question is condensation between window panes a problem.

Use the links below to skip ahead:

What is condensation?
Why does condensation occur between glass panes?
Is condensation between window panes a problem?
What About Condensation on New Windows?
How to fix the problem

What is Condensation?

Condensation is a result of high levels of humidity reacting to colder temperatures on a surface. You will notice excessive condensation after a hot shower, doing laundry, or cooking food. The warm moisture in the air condenses in water droplets on colder surfaces, usually windows or outside walls. Also known as window sweating, any excess in moisture in the home can cause problems.

Now, think back on that steamy shower; the steam escapes the shower area and excess moisture merges with dry air causing condensation on mirrors, walls, and windows. Eventually the condensation will dissipate just like it will on windows. If you want to use that mirror immediately you can usually wipe off some of that condensation, unfortunately that's not the case when condensation occurs between window panes because it's enclosed in an area that we can't reach.

Why Does Condensation Occur Between Glass Panes?

Condensation occurs when warm, moist indoor air collides with a cool surface. In cold seasons, glass can be one of the coldest materials in your home and it attracts the warm air around it. When that warm, moist air hits the surface of the glass the air becomes a moisture droplet. If the seal around the perimeter of the glass has deteriorated moisture can work its way between your glass panes. Eventually, when the desiccant becomes saturated with moisture you'll see condensation and fog on the glass surface that can't be wiped away because it's between the glass panes.

If your home is not adequately ventilated, high moisture levels will create condensation. There are things you can do to reduce this, which we will discuss later.

Is Condensation Between Window Panes a Problem?

Yes. Condensation between window panes is a problem that reduces the efficiency and performance of your windows. Excess moisture in and around your windows can cause the mold and rot in your window. Mold and rot are bad for the structural integrity of the window, the surrounding building materials, and for your health. Some homeowners ignore the problem but there are ways to prevent condensation and those tactics are helpful whether you are experiencing condensation between the glass panes or not.

Pictured below is vegetation between two window panes. This photo is from a home inspection website, the inspector shared the photo to illustrate how a broken seal and condensation can lead to other issues.

What About Condensation on New Windows?

It's normal when condensation forms in a window, even when it's new. Condensation happens when water vapor in the atmosphere condenses into water on a cold windowpane. However, condensation could be a problem if it leads to excessive moisture near your window sills. This might cause water damage, mold, or mildew. Here's some more information about where condensation can happen, how a glass failure warranty can help, and how to prevent condensation.

Checking for where the condensation is happening

Different types of condensation exist, and only one type indicates a failure in a new window. Finding out where condensation on new windows is coming from can help you decide whether you need to do anything about it. Here are the most common types of window condensation and how to spot them.

Exterior condensation

Condensation on the outside of your windows happens when the humidity is high and there's a high dew point. The dew point is the temperature the air must drop to in order to reach 100% humidity. When there's lots of moisture in the air, it often collects on cold glass. Exterior condensation is more common in shaded areas where the windows are coldest. Moisture on windows could also come from a sprinkler or rain. Windows are designed to keep water out of your home, so you usually don't need to do anything about exterior condensation.

Condensation on the interior side of a window

Condensation on the insides of your windows happens for the same reasons as exterior condensation. High moisture levels in the air produce water when the air contacts cold glass. Some condensation is normal, and it can mean that the insulation and seals around your windows are working to keep moisture inside your home.

You may notice condensation occasionally near your kitchen or bathroom, especially when you cook or take a shower. Condensation could also come from a humidifier. However, if water is dripping down the insides of your windows or you're wiping them off several times per day, the humidity inside your home could be too high.

Condensation between glass panes

Some windows have two or three panes of glass. The air between the windowpanes acts as additional insulation. If you have a foggy window but you can't wipe off the condensation, it could be between the panes. This may be a sign of failure from a broken seal. If the seal around the panes of glass has any gaps, moisture could get inside them and cause humidity.

Most double- or triple-paned windows have a desiccant between the panes, a small packet of silica pellets or a similar material. It absorbs moisture to prevent condensation between window panes, but it may not work if moisture levels are too high and the desiccant becomes saturated with moisture.

Glass failure warranty

To get rid of a foggy window when the condensation is between the panes, you could need to replace the entire window or the glass. Many manufacturers' warranties for windows cover seal failure. Before you have a new window installed or replace the pane in an existing window, look at the warranty carefully and make sure that glass seal failure is covered.

Preventing condensation

Knowing how to prevent condensation can help you keep your windows in good condition for as long as possible. You can use a dehumidifier or run a fan for additional ventilation when you cook or take a shower. Putting weatherstripping around windows and avoiding overwatering plants can help as well.

If you have condensation between your window panes, contact us at Brennan. We can help you replace your window and keep condensation from forming.

How to Fix the Problem

A window that is regularly covered in condensation is a problem.

Addressing Window Flaws

Check your warranty and claim on repairs if premature decay of seals has taken place.
Condensation-eliminating chemicals. Although not 100% effective, a professional starts the process by drilling holes into the outer window pane. They then inject a condensation-eliminating chemical in between the panes, and a vacuum out extract air. The hole is then sealed.
Replace glass. Insulated glass units (IGU) can be ordered from window manufacturers. A trusted window professional can replace the glass for you, as long as the seals are still intact. This is an option if there is a crack in the glass.
Replace window. If the window frame shows its age with cracking paint, chipping, and fading, it may be time to bite the bullet and invest in some new windows. Window replacement is the best long-term solution.

General Moisture Management in the Home

Your windows aren't that only structures and surfaces that can suffer damage due to moisture. Walls, doors, and ceilings can also bear the brunt of the damp. Curtains, artworks, and anything close to the developing mold will also be affected. For general moisture management, try the following things:

Ventilate excess moisture. By installing vents and exhaust fans in your bathroom, kitchen, or any other room in the house that is prone to moisture build-up (the basement that contains your laundry station), you can reduce the humidity in the air of your home. By drying the atmosphere, you prevent condensation. Stove fans do a great job by drying out the air from cooking.
If window replacement is out of the budget try installing storm windows to provide a secondary layer of protection on your IGU.
Install a dehumidifier in your home.

Condensation between window panes is a defect that warrants calling an experienced window technician. Explain what you're seeing to the technician so they can provide the proper recommendations.