Ed correct that the issue is humidity, not the windows. A good house ventilation system will help. Keep in mind, though, that the low humidty levels needed to lessen condensation are not always the best for the health of the occupants. Once you go below 40% Relative humidity, you create a climate where viruses & bacteria thrive, increasing the likelyhood health concerns. I try to keep my house at about 35-40% even though I know that some condensation is inevitable (You can't change the laws of physics. 70 Degree air with a RH of 40% has a dewpoint of 44 Degrees. Once any surfaces cols to 44 degrees, condensation will occur).