Best Ways to Handle Window Condensation

Frustrated by the mold and mildew that come with window condensation? Find out about some products to clean mold and mildew as well as tips for replacement windows.

LESLIE: Don in Colorado is on the line with a question about window condensation. What is going on at your money pit?

DON: My house has a window. It’s a vinyl, double-pane window that, somehow or another, collects lots of condensation. And this happens, typically, in the winter. And what happens is this condensation has kind of created some mold and some mildew in the channels of the window inside. And I’m wondering, what’s the best way or what’s the best solution or a powder product that I could use in that thing to clean that mold and mildew up?

TOM: Well, first of all, the cause of this window condensation is that the insulated glass in your windows is not really doing a very good job. So when you have the temperature from the outside basically chilling that entire window, making its way across that insulated space to the inside and then the warm, moist air inside your house strikes the glass and condenses, that’s what causes the steady stream of moisture. And one of the things that can happen when things get wet is it can grow mold.

So, basically, what you have now is kind of a maintenance headache. And it’s just going to be a matter of keeping that clean. You asked what can you use to clean that, to treat that. You can use something natural like vinegar or you can use something natural like Borax. But it’s basically a maintenance job. You’re always going to have to be cleaning and drying those spaces out. Because unless you change your windows or reduce the amount of humidity inside the house, you’re always going to have this window condensation.

Now, what you might want to think about doing, if you decide to tackle windows, is just do the ones that are the worst first. Typically, they’re on the north and east sides of the house; that’s usually the coldest sides of the house. And use replacement windows instead of new-construction windows, which are going to fit into the old window openings. And they’re a lot easier to install than new-construction windows, where you have to tear off siding and reflash all around it.

So, that’s really your option here. That’s what’s causing it and that’s kind of what you’re up against. It’s basically going to be a maintenance issue until you replace those windows.

DON: Thank you very much for the suggestion.

TOM: You’re very welcome. Good luck with that project.