Some windows may have just a single seal.
High quality vinyl windows are getting condensation why.
Their old windows didn t do this so the new ones must be defective.
None of the other windows sweat.
All 3 of these windows were replaced 15 plus yrs ago.
I am a new house homeowner with what i thought were high quality fiberglass triple pane windows and i too have condensation on the bottom of my windows when the outdoor air temperature is very cold below 0 f and the indoor air temperature about 60 f even though the indoor rh is usually less than 35 because i use an hrv.
New windows are not supposed to get wet inside.
If one seal fails resulting in a broken window seal the other can at least for a while pick up the slack.
With double pane windows you should be able to sustain somewhere around 50 to 55 percent relative humidity indoors on a 40 degree night and not get condensation on your windows.
All of the others were replaced at the same time maybe 10 yrs ago.
The odd thing is the mbr has 2 windows but only the one on the back side sweats.
Just like the dew evaporates off of your car and your lawn it will evaporate off your windows as well.
If the problem is only occurring on select windows it s possible you have a draft problem.
But new windows often seal air leaks and a tighter house means elevated humidity.
High humidity isn t the only reason for interior condensation.
Every year we get calls from a customer or two asking why they have condensation on the outside of their brand new windows.
Condensation on new windows makes homeowners angry.
For double or triple pane windows.
This even happens on newer homes that are well insulated.
Most high quality double pane windows manufactured today have two perimeter seals an inner seal that resists water aging and corrosion and an outer seal that provides rigidity and strength.
3 windows on the back of my house get condensation in the winter which is right now.
If there is moist air coming into the house around a particular window that moisture will collect on that window pane first.
If you think that you have condensation between the windows be sure to clean them off first.
Try cleaning the windows.
If you live in an old house with equally old windows take note of where this window condensation appears.
In fact the new windows are performing better than ever before.
Take a closer look at the condensation on the windows.