One of the main gripes UK homeowners have during the cold winter months is the build of condensation on their windows. This can be a real annoyance and, in some cases, can even cause actual damage to the home. Condensation on the inside of your windows is caused by an excessive amount of moisture inside your home. This is more common in winter as any houses will generally have their windows closed to keep their homes nice and warm, trapping any airborne moisture inside. When the warm air inside the home meets the cold windows condensation is formed.