What Causes Ice Inside Windows?

When temperatures drop in winter, it’s not uncommon to see ice and snow outside and maybe even a little bit of frost on the outside of your windows and storm doors. Occasionally, though, you might notice a bit of ice building up on the inside of your windows as well. It’s easy to overlook this as just a sign that the temperature has really dropped outside, but that can be a mistake.

Ice appearing on the inside of your windows is usually a sign that there is something going wrong in or around your windows. At best this can drive up your heating costs during the winter, sometimes significantly. At worst, you might be looking at leaks or other damage that could lead to significant repairs down the road. So if you notice ice on the inside of your windows, it’s important that you take action sooner rather than later.

Ice Inside Your Windows

When ice appears on your window interior, it’s typically a sign that moisture is condensing on the glass and then freezing as a result of cold air making it through the window barrier. This can occur in a few ways, including cracks or gaps in the window frame or damage to the window itself. The cold air cools down the window glass, making it cold enough for the water in the air to condense and freeze on the glass surface.

This can be problematic if the air leak is a result of cracks in the glass or window frame, as ice can build up within the crack as well. As the ice expands, the crack itself can widen. Multiple freezes over the course of the winter can cause increasingly worse damage, resulting in larger cracks or leaks by the time that spring rolls around.

Addressing the Root Cause

There are a few different ways that you can treat the problems that cause ice to appear on the inside of your windows. If you can’t find any signs of damage on or around your windows, it’s possible that the icy buildup is simply a result of your home’s humidity being too high and the windows themselves not being sufficient to keep all the cold air out. If this is the case, you can usually get rid of the ice by using a dehumidifier to reduce your home’s humidity or using home exhaust fans to circulate humid air out of the home. This will prevent ice from building up and potentially causing problems in the future.

If you do find potential gaps or cracks on or around the window, try sealing them with caulk to keep cold air from making its way inside. The caulk can be removed once warmer temperatures come around so that the window will be functional. Applying thermal plastic sheeting or other barriers over the windows may also help to control your icing issue since it will keep humid air in the house from coming in contact with the cold glass of your window. Other solutions such as putting towels or other cloth barriers in place over potential cracks or placing a small space heater near windows that have icing problems may also work. It’s worth noting that none of these are permanent solutions, though they may help you to avoid damage until better solutions can be enacted.

Fixing Your Ice Problem

In the end, the only way to really fix a problem with ice forming on the inside of your windows is to repair the problem. This could take the form of making repairs to your window frame, replacing cracked or broken glass in the window, or replacing the entire window itself.