Hello. I'm sure this question has been asked in many diffierent ways, but please forgive as I am new to these boards. I had new windows installed in my home 6 months ago (uninsulated vinyl frames, dual pane sliders, there is insulation between the window frames and the wall framing). I am getting about an inch wide strip of condensation around the inside perimiter now that we are in winter. Inside r/h is consistantly running about 43-44%. What can I do to stop this? Is my r/h too high in the house? Thanks.

 

Relative humidity level is good. As long as it is between 35-55% this is good. Condensation is formed when warm, moist air contacts cold surface. Likely, the problem is due to lack of insulation in frames and when the air contacts the cold window perimeter it is condensing. One think that might help is to improve air circulation around window by keeping window treatments open.

 

Open a window about an inch for a day or two and turn on bath fan! condensation will go away!

 

Are these Lo-E and/or argon wiindows?? Manufacturer?? Outside temps?? There are windows and there are good windows. Even the best windows will show moisture given the right interior humidity level and low outside temps. As suggested above, it all depends on your conditions. I have excellent quality windows in my house, but my wife has lots of plants that she brings inside for the winter, they give off lots of moisture and on really cold nights, we get moisture around the glass. But is NEVER freezes, a good sign. As a window installer, I had to ask, what kind of windows.glass.

 

If the temperature outside was 32-70F, relative humidity in the 35-55% range might be fine. But in areas of the country where the temperature approaches 0F, the relative humidity inside your home should not be anywhere near 50%, or you will have buckets of water running down cold window glass.

Many cheap humidistats do not give accurate readings, and it is possible that if the gauge says 43%, it could actually be much higher.

The higher the humidity + the colder it is outside, you will notice condensation even on the best performing glass (low-e+argon or triple glass+krypton). So your problem is not unique... it's typical of this time of year, especially when it is nice one day (the RH inside the home likely rises) and then cold the next.

Airman's suggestion may work, because normally cool winter air is dry. You can also check your heater to see if there is a humidifer control on the unit that needs to be adjusted.

There are also more suggestions in the most recent post that dealt with this topic at: http://forum.doityourself.com/showthread.php?t=286601

 

Are you saying 1" condensation on the vinyl frame itself or on the glass? Also if you are saying the glass, is it on the outside or between the glass?

 

I will try to answer all of the questions here. The windows are Gorell Lo-e gas filled (I believe argon). I live in minnesota and the temps were in the low 20's. R/h was measured with a digital hygrometer, so that should be fine. The condensation is forming on the glass, not the frame. Condensation is on the inside of the house on the glass, not between the panes.

 

Improving air circulation around the window by pulling back or opening window treatments that block air and heat from the glass will be helpful. Don't forget to run your kitchen and bathroom vent/fans for 20-30 minutes after using these areas to eliminate excess humidity.

 

40%RH to high for twenty degress. Open window and turn on bath fan.

 

Interestingly, we just completed a window job (using Gorell windows) for one of my boss's friends and had the same problem. As you mentioned, the condensation occurs on the lower 1" of each pane of glass. His cheap digital indoor/outdoor temp/humidity gauge said 39-42% humidity, but when you came into the house from the cold, it felt much higher. He had a very humid basement and his furnace was circulating that air throughout the house. (there were even cold air returns located right next to the basement floor) He had also been painting, which adds humidity to the home. When the double-hung sashes were tipped down, water would stream down the glass, since it had been collecting in the bottom extrusion.

I suggested that he talk to an HVAC expert about improving the air exchange in the home. The idea being that more fresh (dry) air should be introduced into the home instead of recirculating that musty humid basement air. - which is basically what airman's suggestion involves.

I also suggested to my boss that we should get a couple new window sashes from Gorell- except with high performance triple-glass. We would install the new sashes in one of the rooms where windows sit side by side as a sort of "test" to see if the triple glass would help resolve the problem. (the window sashes simply get removed and the new ones get popped in place) But I'm not sure that my boss liked the idea.

At any rate, that might be a possible solution for you, and might be something that your window company might do. If I find anything out that resolves our customer's problem, I will be sure to post back and let you know. In the meantime, I'd try airman's suggestion as a way of attempting to lower your humidity.

For an interesting read, and possibly a science project (if you like math), go to http://biomet.ucdavis.edu/frostprotection/Measure%20Dewpoint/fp003.html

It explains an easy way to determine the dew point in your home. The dew point, of course, is the point at which water condenses on a cold object, such as a cold can of soda, or your bathroom mirror during a hot shower. As you know, the edge of your windows is cold enough that water is condensing in that location.