Condensation on Windows: What It Means and How to Fix It

If you've noticed fog or moisture on windows, you're not alone – and you’re asking the right question. Window condensation is a common occurrence, especially during colder months or in humid environments. But is it a problem?

Is Moisture on Windows Normal?

The short answer: sometimes it’s totally normal, and sometimes it’s a sign your windows are failing.

This handy guide from Centra Install Pros will help you:

• Identify where the condensation is forming (outside, inside, or between the glass panes)
• Understand what each type means
• Learn how to reduce humidity in your home
• Know when it's time to consider window replacement

Types of Condensation on Windows

1. Condensation Outside the Home

What it means:

This is the least concerning type of condensation. It occurs when warm, humid air hits the cool outer surface of your window – usually in the morning or during seasonal temperature swings. Think of it like dew forming on grass.

Why it happens:

• Cold overnight temperatures followed by warm air in the morning
• High-performance energy-efficient windows that keep indoor heat from escaping, causing the outer pane to stay cold

Should you worry?

No – in fact, it means your windows are doing their job by insulating your home well.

What to do:

• Wait for the sun to rise – the moisture will usually evaporate by mid-morning
• If it's happening frequently on windows with older wood or aluminum frames, it might be time to consider an upgrade to modern energy-efficient vinyl windows

2. Condensation Inside the Home

What it means:

This is a sign of indoor humidity. The warmer, moisture-laden air in your home is hitting the glass, causing water to collect. This often appears in:

• Bedrooms (especially overnight)
• Bathrooms after showers
• Kitchens during cooking

Why it matters:

While not a window issue, interior condensation can cause mold, mildew, musty smells, and even damage walls and sills over time. It’s a warning sign that your home needs better ventilation.

Fixes:

• Use bathroom and kitchen exhaust fans – ideally with a dehumidistat
• Crack windows or doors open briefly each day to circulate fresh air
• Keep blinds and curtains open during the day to let air move around by the window
• Run a dehumidifier if necessary
• Ensure your dryer is properly vented to the outside

3. Condensation Inside Windows (Between the Glass Panes)

What it means:

This is the most serious form of condensation – and a sign your window seal has failed. When seals break, window performance is greatly diminished. air and moisture seep between the panes, creating foggy glass you can't wipe away.

Why it's a problem:

• The insulating gas between panes has escaped
• Your window is no longer energy efficient
• Moisture buildup will only worsen over time

Common causes:

• Age-related wear and tear
• Poor installation
• Inferior frame materials (e.g., metal that doesn’t expand/contract with the glass)

What to do:

This is a service issue and typically requires full window replacement. Simply replacing the glass may temporarily improve appearance but doesn’t fully restore insulation performance.

Moisture on Windows: When is it Time to Replace Them?

If you're dealing with persistent condensation between the glass panes, it’s time to look at upgrading. And when you do, make sure to choose a window company that provides a high-performance product with a top warranty.

Why Choose Centra Install Pros for Your Window Replacement?

When condensation between panes tells you it’s time for new windows, trust the team that handles design, manufacturing, and installation – all in-house. Here's why homeowners consistently choose Centra Install Pros:

No Subcontractors – Only Trained Employee Owners

Every window is installed by local, in-house pros who are 100% invested in your home’s outcome. Centra is 100% Employee Owned, meaning extra care goes into every single project.

30-Year Fully Transferable Warranty

Peace of mind for decades. Centra covers frame, glass, installation, and labour with an industry-best warranty. Because the glass is covered, in the unlikely chance you ever experience condensation between the panes again, you know you’re backed by a company who’ll fix the problem – even 30 years down the line!

Built for Local Climate

Centra’s windows are designed for year-round energy savings and sound reduction – no matter your environment. They’re manufactured in BC and Alberta, so you’re working with a team that understands the unique needs of your province.

Huge Energy Savings + Exclusive Efficiency Plan

Centra offers windows that qualify for government rebates and loans where applicable – plus access to Centra’s exclusive Window Efficiency Plan to help you save up to an extra $4,500 on your upgrades!

Experts in Complex Installations

From heritage homes to high-rises, Centra Install Pros have delivered results where others couldn’t — with premium performance every time. You know you’re in good hands with Centra’s experts.

How to Stop Window Condensation

If you’re looking for ways to reduce condensation on windows when it occurs inside the home, these handy tips should help:

• Open windows or doors briefly each day to allow air exchange
• Use bath fans with dehumidistats
• Keep blinds and drapes open during the day
• Ensure dryer vents are properly sealed and directed outdoors
• Open louvers and fireplace dampers to allow moisture escape
• Turn down your thermostat slightly to reduce temp contrast

Most homeowners looking at how to prevent window condensation find these tips very helpful. If you’re still having trouble, be sure to check whether the window moisture is on the exterior of the glass pane and not in between them, indicating a broken seal. If you can draw a smiley face on the window with your finger, it’s still likely to be a humidity problem. If not, the condensation could be outside the home – or in the worst case, between the panes.

Final Thoughts: Don’t Ignore Foggy Windows

Condensation on windows can be harmless – or it can be a sign your windows need immediate attention. The key is knowing where the moisture is and what it means.

• Outside condensation? Normal.
• Inside condensation? Improve ventilation.
• Between the glass? Time for new windows.

If you're seeing moisture trapped inside your windows, don’t wait for energy bills to spike or mould to form. Get the problem fixed the right way with Centra Install Pros!

Western Canada’s Top Choice for Windows & Doors

Have an upcoming window and door project? Reach out to the experts at Centra Windows & Install Pros for a free consultation! If you have any questions regarding this topic or anything else to do with windows, contact a local Centra Employee Owner at 1-888-534-3333 or drop us an email at info@centra.ca. Follow us on Facebook and Instagram to stay up to date, and test your window knowledge on LinkedIn.