What Does Window Condensation Mean, and Should You Be Worried?

You’re enjoying your morning coffee and glance out the window, only to notice condensation between the glass panes. Is it normal? Is it a sign of a problem? In Michigan’s humid summers and frigid winters, window condensation is a common issue—but not all moisture is created equal.

Here’s what that foggy glass could be telling you and when it’s time to take action.

1. Understand the Types of Condensation

Interior Condensation (on the inside of your windows):

Occurs when indoor humidity levels are high and warm air meets a cold window surface. Common in winter.

Exterior Condensation (on the outside of your windows):

Appears in the summer when warm, humid outdoor air hits cooler glass. Usually harmless.

Between-the-Glass Condensation:

This is the type you need to worry about. It means the seal of your double- or triple-pane window has failed, allowing moisture to leak inside the unit.

2. Why Seal Failure Happens

Windows expand and contract with temperature changes—a big issue in Southeast Michigan where temps can swing from -10°F in winter to 90°F+ in summer. Over time, this stress can break down the seals.

Other contributing factors:

• Poor installation

• Low-quality materials

• Excess UV exposure

• Age (especially in windows older than 15 years)

3. Signs You Need Window Replacement

If you’re noticing fogginess or visible water droplets between panes, it’s a clear sign the window unit has lost its insulating properties. This can lead to:

• Increased energy bills

• Mold or mildew buildup

• Drafty rooms

• Decreased home value

Pro Tip: Check for discoloration or a cloudy film that doesn’t wipe off from either side—this confirms a seal failure.

4. Solutions for Foggy Windows

Option 1: Full Window Replacement The most effective long-term solution is replacing the entire window unit. Brands like Polar Seal Windows and Marvin offer highly energy-efficient, multi-pane windows built for Michigan’s climate.

Option 2: Glass Replacement Only

Some companies offer insulated glass unit (IGU) replacement without removing the full frame. This is more cost-effective but doesn’t solve frame or installation issues.

Option 3: Defogging Services

This is a temporary fix involving venting and sealing the glass—but it doesn’t restore insulation or prevent re-fogging.

5. Preventing Future Condensation

• Use dehumidifiers or exhaust fans to manage indoor humidity

• Upgrade to ENERGY STAR® certified windows

• Choose window frames and seals rated for extreme weather zones (like Southeast Michigan)

6. Why Act Now?

Window seal failure compromises your comfort, energy efficiency, and indoor air quality. With utility costs rising, now is the time to make smart upgrades before another harsh Michigan winter rolls in.

At Home & Door, we provide expert window evaluations and offer high-quality replacements from leading manufacturers. Whether you're seeing early signs of condensation or dealing with fogged glass throughout your home, our team is here to help you find the best long-term solution.

Call us today or visit our website for a free quote!

Call 248.399.9900