Dirty Windows are caused primarily by 5 factors:

1. Pollen
2. Insect & bird droppings
3. Dust
4. Pollution
5. Direct Contact (think kids and pets)

If these are present on the glass when it rains, the rain simply attaches itself to the dirt and often makes the windows even look worse.

However if the windows had been clean, then the rain would simply sheet off the clean glass and they would continue to remain clean.

Some property managers of large complexes are aware of this and therefore have their properties’ windows cleaned during the rainy season.

   1) They get more for their money since the windows will stay cleaner longer.

   2) Their customers also have a more enhanced winter by not having to look thru dirt streaked windows.