What causes windows to fog up?

Answer by  Emr (698)

Your house is a small ecosystem and can experience meteorological changes just like outside. If the air is warm and damp in the house and colder outside, the air contacting your windows hits the dew point that causes condensation to form. Things like boiling a pot of liquid on a cool day or taking a hot shower can cause it.

Answer by  Danie (993)

Windows fog up due to the humidity inside the car as compared to the humidity outside. It helps to run the A/C.

Answer by  Amom (701)

Condensation causes windows to fog up. Ithappens when warm air touches the cooler glass. Water in the air when it touches the glass becomes solid causing the appearance of fogging.