If you’ve ever looked at your windows on a cold winter morning and noticed a layer of ice building up on the inside, you’re not alone. This is a common issue in cold climates like the Grande Prairie region, especially during a sharp drop in outdoor temperature.

That frosty buildup might look harmless at first, but once it melts, it can lead to water damage, mold growth, and damaged window frames. The good news is, there are simple ways to manage it and prevent it from happening again.

What Causes Frost on the Inside of Windows?

Frost forms when humid indoor air comes into contact with a cold surface, like the glass on your window. The colder the weather outside, the more likely this is to happen—especially if your home has high humidity levels.

This usually happens:

• Overnight, when temperatures drop and heat is turned up
• When blinds or curtains trap moist air against the window
• If your home’s ventilation system is not removing humidity fast enough

The result is condensation that quickly freezes into a layer of frost or ice.

Why It Matters

When frost melts, it turns into water that runs down your window frame, onto the wall, or into the sill. Over time, this can cause:

• Warped or rotting window frames
• Stained drywall or peeling paint
• Mold growth in hidden areas
• Poor indoor air quality

Stopping the ice from forming in the first place is the best way to avoid these issues.

How to Prevent Frosty Windows

1. Keep Air Moving Across the Windows

Do not keep blinds or curtains completely closed all the time. This traps moist air between the fabric and the cold glass. Keeping them slightly open allows warm air from your home to move across the window and reduce condensation.

2. Use Your Home’s Ventilation System

Most homes built in the last 20 years include a principal exhaust system. This system is designed to help remove humid indoor air while bringing in fresh outdoor air.

If your home has one, look for a switch or timer near your thermostat or in a hallway. Turning it on helps lower your home’s humidity levels, which reduces the risk of frost buildup.

You can also run your furnace fan on the “circulate” setting to keep air moving throughout the home.

3. Avoid Using Heat to Melt the Ice

It might be tempting to use a hair dryer or space heater to melt frost quickly, but this sudden temperature change can crack the glass.

Instead, use a stationary fan to gently blow room-temperature air across the window. This will help the ice thaw naturally while your ventilation system works to lower the humidity in the air.

Bonus Tips to Manage Indoor Humidity

• Use exhaust fans in the kitchen and bathrooms during and after cooking or showering
• Avoid drying clothes indoors during extreme cold snaps
• Keep your HRV (Heat Recovery Ventilator), if you have one, clean and running
• Monitor your humidity levels with a digital hygrometer. Aim for 30 to 40 percent indoor humidity during winter

Final Thought

Frost on your windows is more than just a winter nuisance—it’s a sign that your home may be holding too much moisture. With a few simple habits and by using your home’s built-in ventilation system, you can keep your windows clear, protect your home from damage, and maintain a more comfortable indoor environment all season long.