Why is there condensation on the inside of my glass?
Condensation occurs when there is excess humidity in your home, especially when it’s cold outside. In actual fact, windows and doors don’t cause condensation, but they can tell you when the humidity level in your home is too high. Signs of condensation include:

• Frost on door handles and hinges
• Water or ice on windows
• Damp spots or mildew on walls and ceilings
• Moisture on cold water pipes, walls, and floors
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Here are recommended humidity levels for a home set at 70°F/21°C:

How can I reduce the humidity level inside my home?
If you have humidifier, try turning it off or using it less frequently. Another option: open a door or window for ventilation, or install exhaust fans in the kitchen, bathrooms, and laundry room. Awning and casement windows are ideal for kitchens and bathrooms—places that get warm and humid easily.

What should I do about fogging or condensation between panes of glass?
Panes come factory-sealed, so fogging signals a problem with the seal, not air leakage or humidity.

Why is there condensation on the outside of my glass?
Condensation forms on outdoor surfaces of glass when the outdoor glass temperature drops below the outdoor dew point temperature. This does not indicate that there is a problem with your glass or windows.  It is actually just the opposite.  If insulating glass, it is performing just the way it should.  Here is what happens.  Insulating units that use high performance glass, such as PPG Solarban 60, are designed to reduce the amount of heat that flows from inside of the building through the glass to the outside during cold weather. 
Since the insulating unit keeps more heat inside, the outside glass surface stays colder. If the outdoor surface temperature actually drops below the outdoor dew point temperature, condensation may form.  If the outdoor humidity is low and if wind blows against the glass, condensation will usually not appear.  On cool clear nights, where there isn’t any wind and a high relative humidity, condensation often forms on outer glass surfaces.