There is good money in window cleaning, but you need to price your services correctly, do good work, and target the right demographic. Window cleaning customers are mostly pretty financially well off. You need to realize this when designing your marketing campaigns. Don't flyer tract house neighborhoods. Don't use cheesy used-car marketing jargon. Make sure to look clean cut and don't swear or smell like cigarette smoke when you are on customers property. Common sense, but it needs to be said. You don't want to look like the some of the crusty painter or drywall guys with 4 days of stubble, and a hung-over look. High end cleaners need to cultivate a professional and polished image. That being said, you can make $200-$500 per house easily, pricing your windows at $4-$8 per pane (inside & out). I would recommend starting at $4-$5 per pane at first.
Bainbridge Island Window Cleaning