Question about electricity usage.

Hi, I recently installed a Window A/C in my home, and was wondering if someone could provide me some answers to a couple questions.

So, as I understand it, to find out the cost of running my A/C, I would take the Amps and Volts, multiply them together, and then divide by 1,000 to get the kWh.

In this case, the sticker on my Window A/C rates it at 4.5 Amps, and 115 Volts. So would this mean the max amount of power it can draw is:

4.5 x 115 / 1,000 = 0.5175 kWh ?

Then I would multiply that by how many hours per day I plan to use the A/C. For instance:

0.5175 x 8 = 4.14 kWh ?

So, the max I could use in 8 hours time is 4.14 kWh. Is this correct?

There is no possible way that the A/C could draw more power than that, correct?

So, assuming that is correct, the max I pay per kWh on Tier 4 is $0.35. That means the most it could cost per 8 hours is ~$1.45, again, correct?

So say in a 30-day period, if I run this A/C 8 hours per day, it should roughly equal about ~24.2 kWh, or $43.47 total for the month, correct?

Basically, the biggest thing I'd like to know, is if there's any possible way that the A/C could use more than 0.5175 kWh (per hour). It seems to me that it would not be able to do that in any way, and if it attempted to do so it would either trip a breaker, start a fire, or blow up. Sorry if any of those are incorrect, I don't have much (if any) knowledge in this area, those would just be my guesses.

Just trying to make sure I know how my different appliances run and how much money they cost so I can attempt to keep a low power bill and not use up as much energy.

Thanks for any help!

Or you could go to Home Depot or a number of other places and buy something calles a Kill-a-watt, there are others that work like it that accurately measure how much a device pugged in through it uses over a period.

Because if ANY assumption is incorrect... then all your math is going to be off.

Not quite. There are more factors than just a label. For example, startup amperage is always higher. Any resulting drop in voltage, during say a brownout, will increase amperage. Tripping a breaker has no bearing on the KWH, only Amperage. It will not start a fire or blow up. Any factor that causes the AC to run harder will increase amperage draw. So, your numbers are probably close but I would err on a higher usage KWH. Must be a fairly small unit at only 4.5 Amps