I actually addressed this not too long ago and got some great feed back as to the cause.........since then I have come across some rather confusion information and thought I would run this buy the forum. First I have read where contacting Anderson is almost impossible. I have the standard flip up 28x13 basement casement windows, they face the south and sometimes I suspect when the sun in the winter his them, some condensation will form.....not allot but something that concerns me. My original thought was to install a storm on the outside, something that would take the wind chill and temper it abit; actually wondered if Anderson made an insert with glass like the screen. Some see to think this is a waste of money, the air gap formed between the window and the screen will do very little if anything. Any thoughts? Then I read someplace where the real solution is a quilt cover, one that can be made as a curtain or actually affixed on the window frame itself with velcro...........this will keep the warmer temp in the basement off the outside glass and eliminate the condensation. This was new to me; any thoughts as whether this is the correct way to handle condensation?

Basement is not heated, temp in the finished basement in the winter probably drops to maybe 57 during Dec-Feb.

Would love some feed back, I suspect some have had similar issues and have found resolved either with storms or an inside solution.

 

What is the condition of the caulking around the windows, inside & outside? Is air flowing from one side to the other?

 

No real air flow, caulking inside as well as outside is just fine, in fact the windows actually seal very tight when they close,

 

Hi David,
Condensation forms on the basement side of the glass based upon the surface temperature and the relative humidity in the basement. It's called the dew point. This dew point exists everywhere, inside your walls, kitchen, attic, but is a different number in each location, based upon temperature and RH.

Adding a storm to the outside, or a simple layer of plastic doubles the insulation value of a single glass window., basement or otherwise.

Adding a window quilt to the inside, a real one that blocks any basement air from flowing between the glass and the quilt, will lower the glass temperature, but reduce the windows access to moist air. The lower temperature at the glass surface actually increases the risk of condensation, that is why you need to protect the area from any basement air. Quilts can have a little better r-value over a layer of plastic, but are expensive and hard to find. And, if the rest of the concrete foundation is not insulated, the extra insulation would be of no value. An 8" concrete wall is R-1. Single pane of glass R-1.

Remember, it is not the basement temperature, it is the surface temperature of the glass and its access to moist air.

Bud

 

My car has condensation on it every morning, should I cover it with a quilt.... just kidding!

Good answer bud. Either plastic or storm windows should raise the temperature of the glass slightly, and may not eliminate condensation, but they will make it less likely to occur. If the condensation is on the inside in the winter (I guess he never said) then a layer of plastic on the interior would be a vapor barrier that would separate the cold glass from the warm moist air in the basement. But if the condensation is on the outside, it's likely that adding a storm window would only transfer the condensation (dew) to the outer glass surface. Just like a car will get condensation on it every morning when the dew point and surface temperature of your car cross paths.

 

You are in a green grass state so lowering the rh would stop this.