It’s great fun for the kids to draw in the condensation on the windows of the bus, but what does it really mean in your home?  Should you reduce the humidity in your home, get replacement windows or simply enter your kids in art class?   

Outside condensation

Exterior condensation occurs when the air outside is warmer and more humid than the window panes themselves.  This type of condensation appears when the dew point in the air is higher than the temperature of the glass.  The moisture gathers on the glass pane and then turns into water droplets (sometimes frost), making condensation on the outside.  This typically occurs when there is a cool night after a warmer day, mostly during spring or fall.

Indoor condensation

Whenever the temperature in your home is warmer or more humid than on the outside, you can experience condensation on the inside of your windows.  The warmer the air, the more moisture it can retain, so when the air comes in contact with the colder glass surface, the moisture is released in the form of condensation.

All this can get very confusing.  Here is a great video that explains it and it slightly entertaining at the same time!