How to Solve Window Condensation
LESLIE: Steven in Iowa is calling in with a question about his parents’ house. What can we help you with?
STEVEN: Yeah, guys. My dad built Mom and Dad’s house back in 1956.
STEVEN: And the problem we’re having now is the interior of the windows are just constantly sweating water; condensation.
STEVEN: And I’ve been told by the heating and cooling guys that the house is built too tight, so I just wanted you guys to …
TOM: More like you have inefficient windows, Steve.
STEVEN: You think it’s just a window problem?
TOM: Yeah. I mean here’s what happens: if you get a lot of humidity in the house and it strikes the cold glass and then it condenses, the moisture is released from the air just like when you take an iced tea glass out in the summer. You get water on the outside of it.
LESLIE: And it gets all sweaty.
TOM: That’s what’s happening here and it may be that those 1950 windows are just not very well-insulated, which is completely understandable, and that’s where you’re getting all the condensation.
Now, that said, there are things that you can do inside the house to reduce humidity. One thing to check is to make sure that you have good ventilation all the way through the house and up into the attic, because you get a lot of vapor pressure that forms in the house. It works its way through the walls, it gets up in the attic and has to be released.
And if there’s not good ventilation there, like good ridges and soffit vents – which would be uncommon in a 1950s house; it’s something that has to be added after the fact – you can get a lot of humidity. If you don’t have exhaust fans in the bathrooms and exhaust fans in the kitchen, things like that – again, somewhat common in an older house – then that can contribute to it.
But I think the issue here is not so much that you have too – a house that’s too tight, in that you just have a house that has some efficiency issues.
LESLIE: Yeah. And homes are being built more tightly today, so your dad was right on par with, you know, modern building standards.
STEVEN: To replace the windows right now, will I still have the same problem, because I haven’t made the rest of the house more efficient to …?
TOM: No. What you’re going to find is that when you replace the windows, that the new glass is going to be pretty much the same temperature as the interior walls and so it’s not going to condense on it anymore.
LESLIE: But I would still look into a bathroom vent fan, proper exhausting in the kitchen area, just to make sure that you get extra moisture when you create it, out of the house.
STEVEN: OK. I sure appreciate you guys’ help. I listen to you all the time. Love you guys. Bye.
TOM: Alright. Our pleasure. Thanks so much for calling us at 888-MONEY-PIT.