Window Washing: What Does It Cost?

Angie's List says the charges are generally per pane of glass, $2 to $7 dollars.  

Window cleaning generally is priced by the number of panes of glass. An ordinary double-hung window consists of two panes.

The typical window washing cost runs from $2 to $7 per pane, according to CostHelper. Alternatively, some companies charge an hourly rate. Angie's List members report paying an average of $266 for a full house window cleaning, which may include screens and doors.

For best results, it’s generally a good idea to have your windows cleaned twice every year. However, a number of factors, including whether many windows face the ocean, or your house is exposed to frequent storms, can affect how often your windows will need cleaning. 

Though I'd never heard of CostHelper.com, I certainly am not impressed.  At all.   

Here are a few more resources on pricing out window cleaning.