What Causes Condensation On Windows?

What Window Condensation Can Tell You About Your Home

Condensation on windows happens when warm, moisture-filled air meets colder glass. As the air cools, some of that moisture turns into water droplets. Where the condensation appears can help you tell whether it's normal or whether it’s a sign that your windows need attention.

Earthwise Windows & Doors has served customers since 2002 through a national network of independently owned and operated regional manufacturers. Our windows are designed for specific regional climates and meet or exceed ENERGY STAR® requirements. The key is knowing what’s causing the moisture and whether the solution starts with your home’s humidity or the window itself.

So, when is window condensation a problem? In this blog post, we’ll review when window condensation is normal, and when it should be addressed.

Why Is There Condensation On The Inside Of My Windows?

If you’re seeing condensation on the inside of your windows, indoor humidity is usually the main cause.

Everyday activities like showering, cooking and doing laundry add moisture to the air. When that warm air reaches cold window glass, the temperature drop can cause moisture to collect on the surface.

A little condensation on a cold morning is generally different from seeing windows that are regularly covered in water. If moisture frequently collects on the glass or runs onto the frame and sill, your home's humidity levels are probably higher than they should be.

When Does Window Condensation Become A Problem?

The occasional foggy window is not necessarily a cause for concern. It is worth taking a closer look when condensation becomes excessive or appears somewhere it should not.

Excessive Condensation on the Glass

If enough condensation forms that water begins pooling on the windowsill or running down the frame, do not ignore it. Ongoing moisture can damage the window and the area around it.

Condensation Between Window Panes

Condensation between the panes of a double- or triple-pane window is a different issue.

If the glass looks foggy but you cannot wipe the moisture away from either side, moisture may have entered the insulated glass unit. This indicates that the seal around the glass has failed and the window is no longer performing as intended. 

Unlike ordinary condensation on the room-side surface of the glass, moisture trapped between panes is a reason to have the window evaluated.

How To Stop Condensation On Windows

If moisture is forming on the interior surface of your windows, reducing indoor humidity and improving airflow are good places to start.

You can:

• Run bathroom and kitchen exhaust fans when creating moisture
• Use a dehumidifier if indoor humidity stays high
• Keep air circulating around your windows
• Wipe away standing moisture rather than letting it collect on the sill

Keep in mind that some window condensation during cold weather can still occur even when your windows are performing properly. The goal is not necessarily to eliminate every trace of moisture, but to address frequent or excessive condensation before it begins affecting your home.

Does Condensation Mean I Need New Windows?

Condensation doesn’t always mean you need new windows. Moisture on the inside surface of a window is often tied to indoor humidity rather than a problem with the window itself.

However, condensation between window panes, persistent drafts or other noticeable changes in window performance may point to a larger issue. If your windows are older or you are seeing several of these signs together, it’s worth having them evaluated.

Choose Windows Built For Your Climate

If your current windows are no longer performing the way they should, Earthwise Windows & Doors offers energy-efficient replacement windows designed with regional climates in mind. Earthwise products are made in the U.S. through a network of regional manufacturers, giving customers the benefit of local expertise backed by a national brand.

Find an Earthwise manufacturer near you to explore replacement window options for your home.