Condensation on brand new windows

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  #1  
Old 12-14-14, 05:50 PM
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Condensation on brand new windows

We recently had brand new Pella Proline windows installed in my son's room. The room is about 10x15. Every night we run his humidifier on the lowest possible setting and only giving it about 8 ounces of water. Every morning the two windows are SOAKED. I think every drop of water ends up on those windows.

It's a warm mist humidifer if that helps.

Is this expected? I've tried ceiling fan / no ceiling fan. With the blinds up and with the blinds down.
 
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Old 12-14-14, 05:54 PM
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I should note this home was built in 1956 so it is by no means an air-tight house. The windows however were installed just last year.
 
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Old 12-14-14, 06:11 PM
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If you take a cold can of soda out of the refrigerator and you bring it into his room, does it get condensation on the outside of the can? If so, it's likely that, yes, the humidity is too high. A humidifier- combined with the moisture that a person gives off simply by breathing- would cause windows to sweat during cold weather.

Sure there are other factors at play... if the bedroom door is shut, that obviously cuts that room off from the ventilation in the rest of the house, trapping moisture inside. If curtains, drapes or blinds are pulled, the windows get abnormally cold since they are screened off from the heat source (the heat from the room). Also, if your HVAC does not exchange or pull enough air out... or if it is not running constantly, there will not be enough air exchange to keep up with the humidity being put into the air in that one room.

Now you didn't provide any information about the windows, but it's also possible they are not locked... perimeters not insulated... or some other factor that would make the window itself abnormally cold. But that's a start. If there is anything you could clarify from the aforementioned items, we might be able to give further suggestions.

Normally when it's cold outside in winter months, your glass temperature will be in the 40's... kind of like a can of soda that's fresh from the refrigerator. If the pop sweats in your house, it's likely the humidity is too high. 25% is usually the winter maximum humidity if you don't want a ton of condensation on your windows.

Old drafty windows provide some amount of fresh air ventilation that keeps humidity levels lower. Newer more efficient windows are tighter and thus may trap moisture inside rather than let it out. Removing old storm windows and replacing with a thin thermal pane also changes the location of the cold surface that moisture formerly may have been condensing on... something you probably formerly failed to notice if it was taking place OUTSIDE the prime window.
 
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Old 12-14-14, 06:32 PM
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Since you mentioned that you are adding "only" 8 oz of water to the air on a DAILY basis... this might prove interesting. I found this on Google, and can't verify its accuracy (I'm no humidity mathematician)... but take it for what it's worth.

A 10 x 10 x 8 foot (800 cubic feet) room can hold:

4 oz. of water at 32 degrees F.
7 oz. of water at 50 degrees F.
14 oz. of water at 70 degrees F.
18 oz. of water at 80 degrees F.

In the above example, humidity would be 100%... at it's MAXIMUM capacity... provided no dry air was being exchanged at all.

(You said your room is 10x15... so take that into consideration. Also consider that 100% humidity is not ideal. LOL.)

The same web site warns:

Air that holds 16 ounces of water at 75 degrees F will hold only 10 ounces at 60 degrees, causing 6 ounces of water to condense out of the air into the room.

So what do you think will happen if you add 8 oz of water to the air when the windows are 40F or 50F? The amount of water that is condensing is directly proportional to the amount that is being put into the air.
 
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Old 12-14-14, 06:37 PM
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We do keep the door shut and the HVAC doesn't run much at night because we turn it down pretty low. He has a space heater in his room so that does exacerbate the ventilation issue.

Condensation is definitely on the *inside* of the window. Even the wood on the window itself sweats.

I just wish we could find a humidifier with a decent humidistat for less than $200 so I could just say: 40% and then turn off.

I think I'm also going to switch to a cool mist humidifier that might humidify the air a little slower. We use one of the Vicks warm mist ones and it seems to put a lot of humidity all at once
 
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Old 12-14-14, 06:42 PM
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Hi Will.
The condensation is telling us the humidity is high and if it is necessary for the person sleeping there then direct a fan at those windows to raise their surface temperature, all-be-it at a small energy penalty. Before the new windows were purchased, there was another option, that is selecting a window with a lower outside temperature condensation point. All new windows will have either a CRF# (condensation Rating Factor) or a CR# (Condensation Resistance) helping you to select the best one for your climate. However, those numbers will only be valid if the inside RH is controlled below some specified level. But it sounds like, as X explained, just too much humidity in that room. Have you measured the RH in there?

Bud
 
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Old 12-14-14, 06:48 PM
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The fan is a good suggestion. You could also try 3M window insulator kits over the window trim. It would be an additional barrier to the cold during winter months. Or add a 3rd pane (storm window) to the new window, if that happens to be an option.

This is a case of not being able to have your cake and eat it too. Your home probably has normal humidity, and for some reason people think they need to add humidity in order to be healthy. How on earth did the human race survive without humidifiers? I think they're an invention of southerners who couldn't stand the dry air when they moved north. Keep in mind that all that humidity- if allowed to continue spinning out of control- will promote mold growth. So is adding humidity really a win-win situation or is it a lose-lose situation. That's for you to decide.

If it's dry skin you're trying to combat, some type of lotion would probably be far less problematic. But I do understand that some respiratory ailments are somewhat relieved by higher humidity.
 
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Old 12-15-14, 08:54 AM
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Was able to fix the problem by just opening his door a crack.

My son is two; the humidifier is supposed to help with colds though I'm not sure how much I believe that.


Thanks for the advice. Looking forward to not having to mop down the windows every morning. Hopefully we haven't caused any permanent issues while doing this.
 
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Old 12-15-14, 09:03 AM
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Have you documented the need for the humidifier? In other words, have you taken moisture measurements in the room without the humidifier to see what the moisture level actually is?
 
  #10  
Old 12-15-14, 09:41 AM
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I used to keep a hygrometer in there; I will add it back to track what levels it as at before and after.

Part of the problem is some advice says to keep it as high as 55% which I know is too high for the windows.
 
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