Condensation on your windows results when the surface temperature of the window is below the dew point temperature of the air in your home.

This time of year condensation on windows isn't all that uncommon; and you have a relatively new home that is likely to be still drying out. From the point-of-view of the windows, your home probably has a good bit of moisture inside.

Have you noticed that any particular windows have more or less condensation than other windows? Is the condensation occuring at a particular time of day? Do you have shades or blinds on your windows? If so, have you noticed a connection with the level of condensation?

In order to stop condensation from forming on the surface of a window, you either have to lower the dew point temperature of the air in your home to a level below the dew point temperature of the window surface, or you have to warm up the window surface to a temperature above the dew point temperature of your home, or a combination of both.

Do you know if your windows have a LowE coating? Are they argon filled?

I ask because LowE and argon substantially increase the insulating value of the units versus a clear glass dual-pane window. It is more difficult to prevent condensation on a clear glass (uncoated) window.

The interior surface temperature of a single lite of glass, when the temperature outside is 0 degrees F and the inside air temperature is 70 degrees, will be about 16 degrees.

Add a second lite as in a dual pane window and the surface temperature of the inside lite jumps up to about 43 degrees a very nice improvement.

These are center-of-glass readings and not the temperature readings at the edge of the window where condensation usually forms. And while our typical clear glass dual pane window is going to have center-of-glass temperature of about 43 degrees, if that dual pane has a LowE coating and an argon gas infill then the center-of-glass temperature will be about 57 degrees  a 14 degree improvement over a clear glass dual pane - but, and more importantly, there will be a comparable edge of glass improvement as well, particularly if the IGU (Insulating Glass Unit) was manufactured using a warm edge spacer system.

Warmer glass = less likely to have condensation.

Colder glass = more likely to have condensation.

If possible, you need to warm up your windows. Moving air helps. A small fan blowing on the window can be useful. Keeping shades and blinds open, at least a few inches, can help. A dehumidifier would probably help as well, but mentioned that you don't want one upstairs.

You also need to limit the moisture in your air. Make sure that you use your exhaust fans whenever possible, espcially when cooking or showering or doing laundry (if the laundry area is so equipped).

You might find that opening a couple of windows now and then may help by exhausting some of the moist air from inside your home. However, that is certainly not the most energy efficient solution.

no offense but silverline is NOT agood window. people mistakenly think just because Anderson now owns silverline it must be a good window. well,nothing can be further from the truth. they are a buildeers grade window sold at home depot.

The data posted by oberon is quite interesting as I am currently dealing with a condensation problem also. However mine is due to an expensive but poor window design in which the weep channel slots allow cold air directly into the room. I have heavy condensation with an outside temperature of 20 degrees and an inside Relative Humidity of 36%. I had a commercial thermal imaging company scan these windows as well as an old aluminum contractors window and another vinyl replacement set that did not have argon or low E coating in my neighbors homes. It was done when the outside temperature was 30.5 degrees. The center of the glass temperature on the 40 year old aluminums was 55.8, the non argon, non low E registered 58.7, and the argon filled with low E measured 59.9. Room temperatures were essentially identical. Your data noted significantly larger differences. Is this due to the 0 vs 30 ambient difference or are there other factors?

I forgot I posted this here! I also posted on the decorating board where I frequent.

Oberon - I'm hoping it's just from everything drying out. All the windows seem to be about the same. There ends up being about a 1" wet rim around the bottom edge. After I posted this I didn't have any problems again for awhile. I noticed if it creeps back up to the 40s after being cold I have the problem. As long as it's colder I haven't seen it. The only window we have closed drapes is our master bedroom. Bathrooms have 2" blinds. The other rooms are valance or panels on the side. I have been using the fan in the laundry room now and when I cook. I've been leaving the bathroom fans on longer. Someone over in decorating suggested I make sure everything is being vented outside. I did, and we're good on that area. I'm pretty sure I remember seeing a LowE coating sticker on them.... I need to get ahold of my builder and find out. I can't even find the information of that specific window on Anderson's website. DH will have a cow if I start opening windows. :) We have ceiling fans so I'll start using them more too. I'll keep an eye on it for now.

Krypton - Yeah I'm learning this a little too late. Windows were the last thing really on my mind when we were building. (young and didn't think about it) Builder went on about how lovely the windows are. They tilt, blah blah. We've had a share of fun times with the builder since. :)

Leval - I need to buy one of those hygrometers . .

radio shack sells a hygrometer for about $20.00 with a 3-5%RH accuracy

Don't panic. I'm sure it is a lot from drying out. It probably means they did a good job sealing your house. I had the same thing happen to me. When I noticed it, the windows on the north side away from direct sun were even spotted with mold on the wood rims. I had to clean with clorox mixture, then promptly got a dehumidifier and used it year round for the first year and summers thereafter. The problem did resolve but it took a couple years for the house to completely dry out from new contruction materials. Good luck and be patient. We had even used good quality Marvin windows. I promise the problem will eventually go away.

Forgive me if this is off topic, but I do not believe it is helpful to tell someone that the windows they have installed in their house are not good windows, unless they specifically asked that question. Even if window quality is relevant, I would think that a tactful statement about the specific problem area would come across as less insulting. Just my opinion, and others may disagree.

Sheesharee...I'm not a window expert, but I do know a bit about physics. Condensation on the inside of your windows is only the "fault" of the windows in that their ability to insulate will dictate the temperature of the inner surface of the glass. Unless there is an airflow problem as suggested by leval, I would say that you are experiencing just the right (or wrong, I should say) combination of outside temperature, inside humidity, and window pane temperature. Various brands may offer more or less insulation, but I would be surprised if the temperature difference was that great, assuming the windows are air tight.

Rjoh - Thanks for the heads up. I keep forgetting to pick one up but it's on my weekend store list.

Sunntop - Thank you! That's very comforting. I've been worried about it ever since. Still hoping it's moisture from construction. I've been keeping an eye. Been having that water rim around the edges more. You used the dehumidifer nonstop in your main house for a year + ?

Scottek - I agree with your first paragraph. :) Like I said, I'm not able to replace them at this point.

I mentioned all this to DH and he seems to think it's not the biggest deal. I don't know if he thinks it will vanish on it's own or what. God love him. Still been using all the fans etc. I'm assuming it would be helpful when it gets warmer (spring) to open up some windows and air out?

I emailed Silver Line. I was actually on the Anderson site looking for info when I should've been on the Silverline. I told them what I had in my house...(see above)and asked if the 3001 windows were the same as the 3000 series on their site. They emailed me back saying yes.

So now I'm trying to figure out if they have a LowE coating or are argon filled.. Glass Options LoE², LoE²/Argon, Tempered, Tinted, Obscure
U Factor Clear Glass - 0.47
LoE² Glass - 0.35
LoE²/Argon - 0.31

I'm assuming this is something I'm going to need to ask my builder? What I have listed above is what's on my approved quote. That's all the info I have.

Well, as I think about it, I think I didn't get a dehumidifier until the spring when I discovered the problem and the house was 9 months old. I ran it at least until Dec. then I don't remember exactly when I shut it off. Maybe I did shut it off during the coldest months, Jan.- March. But I ran it many months. There was slight condensation the second year but much less than year 1 and the third year there was none. I continue to use the dehumidifier in the summer. I really think that's fairly common for well sealed homes. The drywall puts out a lot of moisture I've been told.