Fall Window Condensation: Is it a Problem?

LESLIE: Chris in Iowa is dealing with some window condensation. Tell us about it. What’s going on? When do you see it?

CHRIS: Well, I’m noticing it more, as the season begins to get colder, there’s a small amount of condensation on the inside of the bottom of my windows. I was wondering if this is something I need to be concerned about.

TOM: Well, it’s more of an annoyance than anything else but let me tell you what’s happening. The windows are transmitting the temperature from the outside to the inside and the warm, moist air inside of your house is striking that cold surface and it’s releasing its water, essentially, the same way that in the summer you will have moisture that will release onto, say, a glass of soda or iced tea when you put it outside. It’s basically the air, when it’s chilled, can’t hold as much moisture and that’s why the warm air of your house strikes it and condenses.

You can do something simple like if you put shades or curtains over those windows and that stops as much warm air from getting there. That will slow it down. But it’s not really a problem you have to deal with in terms of structure or anything like that; it’s more just of annoyance. I mean if it gets really bad, it could rot out window sills but that’s about it.

CHRIS: OK. Well, that’s a relief. I have new windows and I was concerned that they were going to be rotting out sooner than later.

TOM: Yeah, they shouldn’t be. They shouldn’t be. It sounds like a pretty minor problem.

CHRIS: OK, great.