Have a window AC unit that's from 2001, here are the specs:
- Manufacturer: Kenmore
- VOLTS: 115
- Cooling BTU/HR: 12500
- Cooling AMPS: 11.6
- Cooling WATTS: 1275
- Cooling EER: 9.8
The average electricity rate is 11.04¢/kWh.
As for the hours of use per day, currently varies anywhere from 12 to 24 hours of use per day, so I'm not sure how to deal with that; maybe the easiest way is to just do two estimates, one for 12 hours of use, and another for 24 hours of use.
User Manual is here.
Very possible that I've left out some information, but even with the above information, I still haven't been able to figure out how to even do a rough comparison.