External condensation on vinyl windows

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WASHWIN6
Posts: 12
Joined: Wed May 17, 2006 4:44 pm

External condensation on vinyl windows

#1 Post by WASHWIN6 » Fri Sep 29, 2006 10:19 am

I had all of my old single pane windows replaced this past July. I used Milgard's double pane, argon gas-filled, low-E Superspacer windows. Everything was fine during the warm months. Now, in late September when it is getting cooler overnight (I live in the Seattle area), I am getting a heavy layer of condensation on the outside of some windows. On three of the the windows it covers the outside surface completely except for about a one inch wide band around the perimeter. On the fourth the situation is reversed. The condensation is around the edges and an oval-shaped area in the middle is clear. The other windows have no condensation. Does anyone know what might be causing this?

Window4U (IL)
Posts: 1548
Joined: Thu Oct 07, 2004 8:46 am
Location: Sales and Installation in Chicagoland and Central Illinois

#2 Post by Window4U (IL) » Fri Sep 29, 2006 11:04 am

WASHWIN6 wrote: Does anyone know what might be causing this?
The same reason why there is dew on the grass and on your car windows.
Your windows are performing...be happy of this harmless phenomenon. It means the outside glass is not being warmed up by heat loss from the inside of the home. Your windows are working.
It will go away once the exterior air becomes less saturated with water vapor as winter approaches.
As far as the uneven dew formation...air flow patterns and other conditions can change this effect from window to window. It is normal for it not to be even on all the windows.

researcher
Posts: 129
Joined: Tue Nov 30, 2004 11:39 am

Re: External condensation on vinyl windows

#3 Post by researcher » Fri Sep 29, 2006 12:13 pm

WASHWIN6 wrote:I had all of my old single pane windows replaced this past July. I used Milgard's double pane, argon gas-filled, low-E Superspacer windows. Everything was fine during the warm months. Now, in late September when it is getting cooler overnight (I live in the Seattle area), I am getting a heavy layer of condensation on the outside of some windows. On three of the the windows it covers the outside surface completely except for about a one inch wide band around the perimeter. On the fourth the situation is reversed. The condensation is around the edges and an oval-shaped area in the middle is clear. The other windows have no condensation. Does anyone know what might be causing this?
I also experience the same thing at times since i got new windows. What Window4U said is quite right.

WASHWIN6
Posts: 12
Joined: Wed May 17, 2006 4:44 pm

#4 Post by WASHWIN6 » Fri Sep 29, 2006 1:03 pm

OK, thanks. That makes me feel better. Since I made the post this morning I called the installation company and they also said this is normal. They are sending out an information booklet about it. The thing that confused me was the fact that some windows had it and others didn't. In some cases windows that had it and didn't have it were right next to one another.

chrisexv6
Posts: 83
Joined: Sat Jan 21, 2006 11:27 pm

#5 Post by chrisexv6 » Fri Sep 29, 2006 2:56 pm

Yep, first morning with my new windows I had it on some of the windows. And a window 2' away in the same room *didnt* have it. Definitely has to do with the water in the air and how the air hits the house. One room has 2 windows, both on perpendicular walls. The one shielded by the house didnt have any condensation....the one open to the weather did.

Worried me a little but the great folks here explained what was going on.

-Chris

Guy
Posts: 537
Joined: Thu Oct 07, 2004 12:41 pm
Location: Minnesota

#6 Post by Guy » Sat Sep 30, 2006 7:54 am

It's all about the humidity level outside the home. Relative humidity is the ratio of the amount of water vapor in the air, compared to the maximum amount of water vapor the air can hold at that particular temperature. In simplest terms, it's a ratio of the air's water vapor content to its capacity.

Relative Humidity is called "Relative" for a reason. Relative Humidity is a comparison of the amount of moisture in your air, versus the temperature of the air. Basically, warm air can carry much more moisture than cool air can. When air, with a specific amount of moisture content, is at the temperature where it reaches 100% saturation, the air must begin to release moisture. Meaning that 100% saturation is also 100% relative humidity. 100% Relative Humidity is also known as the Dew Point. When the weatherman tells you that the dew point is 65 degrees, he is saying that when the air temperature reaches the dew point the air will be 100% saturated with moisture and that the excess moisture will be "released" by the air. The result is morning dew on the ground, your car, your home, your tools the kids left out on the ground and last but not least your windows. If the evening temperature does not reach 65 degrees (or cooler of course), then the air will not be fully saturated and you will see no morning dew. Hope this makes some sense!

Another problem that we run into here in the cold Minnesota Winters is moisture on the inside glass after installation. Here's the scenario:

Some of us installers use non heated space to store our windows before their installation date (since heating is a great deal of money). As most of you know we get some real cold periods of the Winter when it goes Sub-Zero here in MN. Now please keep in mind we generally won't do any installations if it goes below zero. But when we get around that 10 above zone it's a go for the installation. We then pull the windows from the cold storage and install them for the customer. Ounce we finish we always receive a call soon after complaining of moisture on the inside of the glass on cold mornings. Then the moisture goes away when the sun comes up. What happens here is the stored windows that have been in the cold for so long now have to acclimate to having one side warm, and the other side ice cold. The Insulated Glass Unit (IGU) is so well sealed that it takes a great deal of time for the inside air space of the IGU to acclimate to its surroundings. In some cases it takes months to correct itself. So don't get alarmed if this happens on a cold weather installation!!!

bhamwindows
Posts: 1
Joined: Mon Oct 09, 2006 10:40 am

Outside condensation, Milgard windows on South facing wall

#7 Post by bhamwindows » Mon Oct 09, 2006 10:50 am

Hello,

I too have just recently installed new super duper wood clad etc. Milgard windows. I have noticed the fogging on the south window, but not the east one that is under the eaves. While I undertstand from this string that this may be "normal" I am concerned that in this Northwest Enivironment ( Bellingham) we will not see through the fog for several months ...say May! I am asking what window could be installed that could be seen through? This is a lot of money to not be able to see through the glass.

Thanks

Stephen Thwaites
Posts: 23
Joined: Wed Feb 08, 2006 10:35 am
Location: Ottawa, Ontario, Canada

#8 Post by Stephen Thwaites » Mon Oct 09, 2006 8:51 pm

It is alot of money not to be able to see through glass, but exterior condensation usually doesn't last for very long. Once the sun pops up the condensation should disappear. So sleeping in can be an alternative....

However, if you really want to get rid of exterior condensation, ask for a window with another low e coating on surface #1, that's the exterior surface.

At a former residence i successfully tried this on a some triple glazed windows that were particularly prone to exterior condensation.

An exterior screen should also work.

RichO
Posts: 2
Joined: Thu Nov 02, 2006 11:50 am

#9 Post by RichO » Thu Nov 02, 2006 2:12 pm

WASHWIN6,

Did you end up having Signature do the install? Are you happy with the work?

Regards,

Rich

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Windows on Washington
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Joined: Fri Oct 27, 2006 11:23 am
Location: DC Metropolitan Area-Maryland/Virginia/DC

#10 Post by Windows on Washington » Fri Nov 03, 2006 3:44 pm

Your windows are working properly...enjoy.

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