I froze yesterday in my office, forgot my jacket.  I even turned up the thermostat, I can hear our a/c unit running all day long (14th floor of 23 floor bldg).  Our building is either too cold or too hot - they can't seem to get a happy medium.  As for windows, I can hear enough of the sirens, car engines, honking etc. that I could only imagine how worse it would be opened.