A lot of the Energy hog fridges that are used in these comparisons are side by sides which are inefficient. Most use between 10.8 -14.8 amps. So Volts x Amps = Watts, and Watts x Hours run x Days = Total Watts, Total Watts divided by 1000 = Kw on electrical bill. This is how they are all calculated it doesn't take into account inside thermal mass, external temperature, open/close excesses, this is figured with fridge set at manufacturer's recommended setting. Just give you an idea of projected cost. That said my 20cubic foot kezzer at 115 volt and 4.3 amp with a run time of 2 hours total run time per day at 30 days per month at 13 cents per kilowatt cost $ 3.86 per month.