Window Condensaton Redux

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By leaving doors open I meant interior doors, where you keep pets.
You dont state at what exterior temps you have 20-25%. I have Pellas and the same BS issues, My Andersons do not condense but all my glass is sealed dual pane Low E Argon. Im Zone 5 Chicago area. If you have nonsealed, non argon, then yes they are even worse than sealed glass.
Poly should be UV resistant, exterior grade is UV resistant.
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m Ransley wrote:

Most of the Ohio winter when I see 20-25 humidity, it's the usual 0-40 outside.

That's what I finally put on. A nice UV outdoor poly rated for (of all things) window jams, frames, etc.
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You might look for and try to fix any large water vapor sources, eg a damp basement floor or walls or a rainwater leak. If you have no major water vapor sources, you may have a fairly airtight house, which is good :-) In many US houses (those requiring winter humidification), air leaks account for more than half the fuel bills. If your house has any exhaust fans, you might turn one on with a humidistat when the indoor RH rises to 50% in wintertime.

That is strange. Perhaps you are measuring incorrectly. The dew point of 20% RH 70 F (530 R) air is roughly 530/(1+530ln(0.2)/9621) = 487 R, ie 487-460 = 27 F. Outdoor air would have to be colder than 70 - 65R1 = 5 F to make the indoor surface of an R1 window 27 F and condense water out of 20% 70 F room air. An R2 window would condense with 70-65x2 = minus 60 F outdoor air, and so on.

Where? If the air pressure inside the house is lower than the air pressure outside, outside air would enter the house. If the outside air is cold, it probably contains less moisture than the air inside the house, so it would have a drying effect. Same effect with windows that leak lots of air.
Your HVAC guy may have been clueless.
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

My basement is dry as a bone. Thank god. My last house didn't have that luxury. :-)

Perhaps. My only "measure" is ye old Oregon Scienticis sensorys with the RH sensor. Eve it it's wrong, it's still relative to itself (%50 down to %25)

Funny. Just this morning, the outside RH was higher than the inside RH, using two of the same sensors. All tings being equal..

Quite possible. The more of them I try, the less help I seem to get past wanting to sell me a new unit with a variable speed fan. :-/

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That outdoor air might contain less moisture, if it's cooler than house air.
Nick
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I think that you spent 10 paragraphs talking about your windows, and the only parts of it that even resembled useful information was "Humidity is around 50%", "The seals might not be good".
The bottom line is, you have two possible approaches, either keep the water(humid air) away from the windows, or make the window surfaces warmer.
Have you checked for actual air leaks? Is this condensation over the entire window, or just on parts? Which parts? Are you sure that what you're getting isn't water-leaks in the wall around the window?
Put a clear plastic seal over the entire window, and see if it moves when the wind blows. Put dessicant between the clear film and the window, and that should solve the wetness issue, because that will keep the WET and COLD separated.
Moving your hot-air supply directly in front of the window or aiming a heat-lamp at them would probably also work, by heating the window surfaces above the dew-point.
--Goedjn
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Goedjn wrote:

Yes, with a stick of insence. I'd say that some of them are, based on the direction of the smoke. But then again, it's hard to tell when you're standing there breathing air and altering the flow of things.

When it's bad, it's just the bottom 3" of the glass, and the metal frame of the glass. This in turn works it's way down between the window and the window frame, and freezes on the window wood, on the frame where the seal is.

It's definatly water rolling down the window and into the opening between the windo and the frame.

I've looked around to find a decent desiccant, usually silica packets, but I'm having a hard time finding such things around here. Is there a specific item or brand you had in mind?

Interestingly enough, almost all of my windows have heat registers below, or right beside them on the outer walls od the rooms.
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On Mon, 17 Oct 2005 14:04:09 -0400, "Christopher H. Laco"

A cloth "snake" stuffed with dried rice ought to work, although you might have to change it periodically. If the root of the problem is cold air leaking around the bottom of the window and chilling the immediate area to below the dew-point, that should help with that, to, although adding weatherstripping or even taking a hair-dryer to the rubber seals might work better. Try cutting some dowels to jam between the top of the window and the lower sash, to shove the thing down harder against the sill, maybe?
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Goedjn wrote:

You know, I've heard the one of the things Pella service tries somethings is bending the sash clips to make the window fit tighter. The one thing I've always felts was that the sash lock handles never did a good job of drawing the window into the frame.
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The experimentation has begun. I snagged some 1/4 weatherstripping and did the worst window upstairs. I'll give it acouple days. When that proves to be useless, I'll move on to the next thing: shrinkwraping that window.
Plenty of time to experiment between now and December 5th when the Pella guy get's here.
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Christopher H. Laco wrote:

The experiment continues. The weatherstripping didn't make a difference. That rules out bad frame seal/air leak.
It did point out something interesting on that window, and possibly others. As I mentioned before, it appears that condensation dripped down the glass into the space between the fram/window, and froze on the window frame/frame/seal.
Well, in the early am during the peak condensation time, the frame and weatherstripping was dry, but there was water on the metal sash below that point when the window was opened. That's curious. There shouldn't be wter there. Hopefully something will turn up when they inspect them from the outside.
For my next trick, the plastic window wrap, and possibly leaving the bedroom doors open (I'll have to get some pet/kid gates).
-=Chris
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On Mon, 17 Oct 2005 11:52:08 GMT, "Chrisotpher H. Laco"

Casement Windows are lousy. Get a box of Mortite Weatherstrip & Caulking Cord to seal the air leaks. Follow instructions.
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