I researched several NYC window cleaning companies and gathered quotes before choosing a service, and Chelsea's was the cheapest I found by 3 whole dollars per window.
Since we had never worked with them before, they sent out John, one of the managers, to walk through our space, verifying our window type and structural details pertinent to cleaning, as well as answering my questions about pricing and scheduling. Robin and Maria at their office were friendly, knowledgeable and quick to respond as we figured out a day and time that worked for my office's busy and unpredictable schedule.
The day of our cleaning, the window cleaners (Joseph and Emerson) arrived on time and ready to begin - however, I quickly realized I had grossly underestimated the number of windows in my office - there were nearly 20 more than we had scheduled time for. Even though this was MY mistake, the folks at Chelsea were incredibly accomodating, changing their schedule to allot more time for Joseph and Emerson to clean the extra windows at the same low price per window.
And even though my mistake nearly doubled the scope and time of the job, they remained polite, hard working and efficient, even pointing out damaged windows (prior to cleaning) so that we could notify our landlord. They also went over their work with me before leaving, so that we'd know exactly what to expect on our invoice. I would recommend Chelsea cleaning to anyone - especially office spaces and studios with lots of windows. :) windows. :)