Doors and Windows - Condensation on storm windows, 2nd story

Condensation on storm windows usually indicate the air leakage or heat loss is coming from the primary window. What occurs hear is the heat is passing the wood window or primary window and condensing on the storm window. Most of the time changing the latch will resolve the problem. What latches on windows actually do is make the primary window tight. If you look at the design of the latch you will see that it is half moon and graded. What this does is push the outer sash up, the inner sash down and then pull them together. After awhile this grade wears down and the window is no longer tight. The result is heat loss and condensation on the storm window. Weatherstripping sometimes works by prohibiting the heat from escaping and by taking up the gaps created by the worn down latch.

I started to reply to this but I need some information. I'm assuming that these are wood windows with exterior aluminum storm windows. Is this correct?

Yes,

The main windows are wood windows and the storms are aluminum.

Eric

You or a previous owner decided at some time that repairing the wood window(s) was not what you (they) wanted to do. That's why the storm windows are there; to make up for the deficiency in the wood window(s.) What I'm going to suggest will (hopefully) solve your condensation problem and another problem you may also have but may not be aware of. That problem is the condensation between the wood window and storm window may be causing the exterior of the wood window, particularily the sill to rot. The quickest and cheapest "fix" is to drill a couple small holes in the storm window(s.) This will allow the moisture between the two windows to escape. Yes, this will reduce the efficiency of the storm window(s) slightly but it should cure your problems of condensation and possible wood rot. If you decide to do this drill a couple small holes in the side of the storm window at the top and a couple more small holes in the face of the storm window at the bottom. These holes at the bottom must be drilled at the very bottom of the storm window. These are to "weep" any water between the windows. Or, you can of course repair or replace the wood window.

Happy Thanksgiving!

John

John,

Thanks for the information. Let me give you a little more detail though, as I already have some pretty good sized weep and ventilation holes in the aluminum storm windows. And yes, I am beginning to get a bit of rot in the sills.

There are 12 windows upstairs, 11 that have older storm windows( with very small weep holes) and one that is a brand new storm window (that has two weep SLOTS, probably 3/16" wide by 3/4" high, at the bottom). If I was only having the problem with the windows that have old storms I would agree that ventilation is my problem. But I have roughly the same amount of condensation in all 12 windows... I'm a bit baffled.

I guess I will just play with them (rope caulking certain areas and see if the situation gets better) for now and see what happens.

Eric

Eric,
I'm a bit baffled too. What I was trying to do with the holes top and bottom was to get some convection going. I thought this might help to dry up the condensation. As long as your in the experimenting mode I have an idea. I'm assuming that you have "triple track" storm windows (one track for the screen and one for each sash.) If this is correct and you can lower the top sash in the storm window down to the point where half of the top sash overlaps half of the bottom sash and the sash stays there on its own, then do it. This is an extreme example of the convection method. Do this on only one window and see if the condendation goes away. For obvious reasons, this is not the solution, but might help you toward one. If this works, then you may need to find a way to put ventilating holes in the top of the storm window in a way that does not allow water infiltration. Your idea to do some work on the wood windows I'm sure would be helpful too. Good luck and let me know what happens.

John