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Basic question about energy costs

  1. Aug 4, 2007 #1
    Hello. thanks to all in advance for any help you may offer me. i have a simple question. i remember being in high school physics being taught how to calculate the cost of an appliance. i am trying to figure out how much it costs to run my window unit air conditioner.

    i thought icould just take how many watts it is rated at(530, which is .53 kw. so if i were to say that every two hours would be a kwh, then would my cost of a kwh be the same cost(roughly, since i estimated that 1.06 was 1 kwh) as running it for two hours? i am confused about this because i dont understand how current has nothing to do with the cost. there are different settings on the AC (it can function as a fan on low or hi, or as an AC on low or hi, how could these cost the same to use?) also, if this is true would that mean that running my AC would be the same as using about 5 100 watt light bulbs?

    please straighten me out im sure im misunderstanding something.
  2. jcsd
  3. Aug 4, 2007 #2


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    Science Advisor
    Homework Helper

    You are correct, the rating is the maximum power it can take and is more a guide to the electric connection needed than the average power it is using.
    You can buy small plug in adaptors which go between the appliance plug and the wall socket and will measure the average current and display the power and cost. They can even store different price at different times and tell you the average over a year.
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