Condensation

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ryan87500
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Condensation

#1 Post by ryan87500 »

I just moved into a house that was built in 2013 in the Chicagoland area. They have Pella proline windows which was manufactured during the period they had issues. The windows seem not to be rotting.

My issue in the bedrooms is when I open the blinds in the morning now that it is dropping to 40s at night the entire window has condensation.

If I open the blinds it disappears in an hour or two. I have one room with no blinds and no condensation issue.

Is this an issue of leaky windows? Don't really have a budget now for windows not sure what I can do if anything.

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Windows on Washington
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Re: Condensation

#2 Post by Windows on Washington »

You need to leave the blinds open if only slightly.

The warm, room-side, heat needs to be able to circulate and move along the glass to keep it warm. When you have the blinds closed, the windows don't have access to any warmth and the temperature will eventually plummet to a point where dew point happens.

Without knowing what your indoor humidity levels are, the fast and simple solution is to open the blinds when you go to bed.

ryan87500
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Re: Condensation

#3 Post by ryan87500 »

Windows on Washington wrote:You need to leave the blinds open if only slightly.

The warm, room-side, heat needs to be able to circulate and move along the glass to keep it warm. When you have the blinds closed, the windows don't have access to any warmth and the temperature will eventually plummet to a point where dew point happens.

Without knowing what your indoor humidity levels are, the fast and simple solution is to open the blinds when you go to bed.
Based on my Ecobee thermostat in the master the humidity is around 53%.

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Windows on Washington
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Re: Condensation

#4 Post by Windows on Washington »

That's way too high for Chicago in the Fall/Winter.

At that calculation, you will get dew point on the window surfaces at 50 degrees which you definitely are getting with your overnight lows.

You need to get that Relative Humidity down to around 35%.

http://www.dpcalc.org/

ryan87500
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Re: Condensation

#5 Post by ryan87500 »

ryan87500 wrote:
Windows on Washington wrote:You need to leave the blinds open if only slightly.

The warm, room-side, heat needs to be able to circulate and move along the glass to keep it warm. When you have the blinds closed, the windows don't have access to any warmth and the temperature will eventually plummet to a point where dew point happens.

Without knowing what your indoor humidity levels are, the fast and simple solution is to open the blinds when you go to bed.
Based on my Ecobee thermostat in the master the humidity is around 53%.
Thanks. I am wondering if it is just because of the season change and the humidity will decrease. The outdoor humidity today is 56% for example.

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Windows on Washington
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Re: Condensation

#6 Post by Windows on Washington »

Open the windows or run the AC to dehumidify.

ryan87500
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Re: Condensation

#7 Post by ryan87500 »

Windows on Washington wrote:Open the windows or run the AC to dehumidify.
If my indoor humidity is about the same as outside why would opening a window help? Wouldnt it just match the humidity level?

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Re: Condensation

#8 Post by Windows on Washington »

When it gets colder. Run the AC.

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Re: Condensation

#9 Post by TheWindowNerd »

The first part of the heating season you have a lot of mositure trapped in the house. Condensation is normally worst in the beginning of the heating season. Another bad time is extreme temperature swings during the heating season.
Other contributing factors: plants inside the house give off a lot of water, a humidifier that is not set properly for the exterior temperature, then there is drying the garments in the house or basement followed by dryer vents turned to the inside to capture the heat.

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HomeSealed
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Re: Condensation

#10 Post by HomeSealed »

All good advice above.... Get some warm air on those windows (open blinds and curtains), and try to reduce the humidity. You can also run a dehumidifier (it will help even if it is in the basement), and/or run your bath exhaust fan for a bit before bed. Regarding your question about matching the humidity, that's only if the temperature is the same inside and out. If it is colder outside, your warm, moist air will move to the outside air the same way that it is moving to the cold glass.

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Window4U (IL)
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Re: Condensation

#11 Post by Window4U (IL) »

A poster named Tru-Blu who used to frequent these boards quite a bit posted this years ago. You may find this interesting and hopefully helpful:
I'm going to throw a lot of statistics at you to address condensation on your windows. Keep in mind that these stats are based on a worst-case scenario of 0° outside and 70° inside, which sounds like it may apply to your climate but is not applicable to warmer, southern climates.

Now for some stats. If a window is clear double glazed insulating glass (doesn't matter if it's wood or vinyl), the center-of-glass roomside temperature would be about 44-45°F. (Incidentally, single pane windows with a storm window would be about the same) Adding a Low E coating to the glass bumps it up to about 52°F, and Low E insulating glass with Argon gas raises the glass temperature to 57-58°F. Not bad for 0° outside. You didn't mention if your windows are Low E; hopefully they are and that they have the argon gas as well.

However, with insulating glass the edge-of-glass temperatures are much lower than center-of-glass. The type of spacer that separates the panes of glass greatly affects the edge temperature, and much could be said about the merits of different types of spacers. Naturally, condensation, and even ice, would normally occur at the edge first, since that's the cold "weak spot." Clear IG with an aluminum spacer has an edge temp of only about 29°F. Low E glass with an aluminum spacer only raises it to about 32°. Then there are "warm edge" spacers, which are warmer and provide more condensation resistance. Stainless steel spacers are about 37° edge temp on a Low E/argon unit, and Superspacer and TPS spacers would be at the top at about 39°. Again, warm edge spacers typically range from 35-39°, but still tend to max out usually in the upper 30°s. So it's normal for windows to be colder on the edge than they are in the center.

Now for the fun part. If you cover a Low E/Argon gas unit with some type of roomside window treatment such as a shade, blind, etc., the center-of-glass temperature drops from about 57° to only 36°. That's an amazing 21° drop. I don't have any exact stats on what that does to the edge temperature, but I would imagine it must drop 5-15° as well. The reason it drops is because the air in the room is no longer freely circulating against the glass. Even a couch or desk in front of a window (or door) will significantly reduce the glass temperature if the furniture is partially blocking part of the window. Condensation often tends to lessen or dry up by mid-day because cold/condensation caused (in part) by the shades being down at night are now opened and the windows now have circulation against them.

Enough stats. Condensation, and worse yet, ice, can NOT occur unless two conditions are present at the same time: high humidity and cold temperatures. The cold temperatures on your windows could be due in part to missing or defective weatherstrip, poorly-fitting windows, faulty installation, or just because of cold winter weather. If you have cold weather but low humidity in the house, condensation cannot occur. Both conditions have to be there. If you're experiencing condensation on your windows, you have too much humidity given the current outside temperature with the existing glass system that is in the home (assuming that the windows are properly installed and not defective in some way). There are TWO basic solutions: raise the glass temperature or lower the humidity. That's it in a nutshell - those two things. More about those in a bit. First, I'd buy a digital hygrometer from Home Depot, Radioshack, a hardware store, etc. to measure the amount of humidity in the house (about $10-$29). You need to know that. Then I'd contact the manufacturer of your new vinyl windows if possible or visit their website for recommended humidity levels for various outdoor temperatures. Most window manufacturers have brochures on condensation and recommended humidity levels. They usually will state that when it's 0 degrees outside your humidity level inside should be in the 20-25% range. (Again, this is a worst-case scenario) I'm guessing your humidity level is significantly higher than that.

RAISE THE GLASS TEMPERATURE - One possibility is to raise any shades up when it's really cold out. As mentioned before that can increase the glass temperature by an additional 21° or more, but unfortunately that leads to a lack of privacy. A compromise is to open them just slightly, maybe 4" to 8", so that warm air can circulate against the bottom of the glass (the most condensation-prone area) and partially warm the glass unit. For your older existing windows, the best solution is often to replace them with modern, energy-efficient windows. But you've already have newer windows with the same issue and it's evidently still not enough given your humidity levels. For those who replace their windows, it's ideal to replace them with windows that have warm-edge spacers, Low E coatings, and gas fillings in the units to hopefully avoid condensation. If someone really wanted to get the absolute maximum condensation-resistant windows out there, there are windows that are triple glazed that have a better performance than what you currently have, but most modern "energy-efficient" windows are made with double glazing and that's usually all that is needed. An advantage of many triple glazing systems is that one can have higher humidity levels in the home before condensation issues would arise. Some even have between-glass shades to avoid temperature drops when closed for privacy. Other ways to raise the glass temperature include taking out roomside casement screens during the winter, using free standing fans or ceiling fans to better circulate air against the glass, and adding another layer of glass or plastic (I hate to see that though - it shouldn't be necessary).

LOWER THE HUMIDITY - The bottom line here is proper ventilation and insulation. One of the best solutions for an airtight home is to have an air-to-air heat exchange ventilator installed to the furnace. It's required by code for new homes in some areas. It brings in the DRY fresh air from the outside and exhausts the stale HUMID air - giving you healthy air to breathe and lowering the humidity to the desired level. New homes are built so much more airtight than older homes, so they often need mechanical help to get air exchanges. Older homes exchanged air by being drafty. Dehumidifiers will help too, but are generally not as effective, since they usually can't get the humidity low enough. Great for basements though. Simply turning down your April Air humidifier probably won't do it - that simply means the humidifier won't turn on, but it won't remove humidity like DEhumidifiers are designed to do. Other ways include running exhaust fans when showering (and leave them on for a while), or simply stop bathing 

In summary, condensation on windows can and will occur under the proper conditions. Even ice can form if the humidity is high enough, the temperature is low enough, and other factors are in place such as restricted airflow to the glass because of window shades. You need a humidity-measuring device to see if your humidity is too high. You need a humidity guide to suggest proper humidity levels. And ultimately somebody has to address raising the glass temperature or lowering the humidity.

jennie
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Re: Condensation

#12 Post by jennie »

:)

JosephKeen
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Re: Condensation

#13 Post by JosephKeen »

Condensation mostly occurs when moist air comes in contact with cooler dry air. You can buy a dehumidifier to reduce the amount of humidity in your home. And make sure that whenever you use the bathroom or kitchen, keep the door closed.

collin
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Re: Condensation

#14 Post by collin »

A dehumidifier might help.

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