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quick numbers for electrical usage

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  • Paul Archer
    I calculated this for my own use, and thought it would be helpful for others. $.14/kwh (going rate in Houston) 120 watts * 24 hours/day * 30 days/month = 8,640
    Message 1 of 3 , Jul 6, 2006
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      I calculated this for my own use, and thought it would be helpful for
      others.

      $.14/kwh (going rate in Houston)


      120 watts * 24 hours/day * 30 days/month = 8,640 watt hours / month
      8,640 watt hours / month = 86.4 kwh / month
      86.4 kwh * $.14/kwh = $12 / month



      So, if you have a 120V appliance/lamp/whatever that uses 120watts of power
      (for instance, a light fixture with 2 60 watt bulbs), and you leave it on 24
      hours a day, it'll cost you $12 a month.

      Since 120 watts at 120V is 1 amp, if you do measurements at your breaker box
      (using a clamp-on amp meter, or "clampmeter"), you can see that each amp of
      measurement (assuming it's for a constant, 24 hour/day load) will cost you
      $12/month.

      You can extrapolate this, of course. For instance, if you have a light with
      a 60 watt bulb, and you have it on for about 6 hours a day, it'll cost you
      about $1.50 a month.
      Or, if you're like me, and you have a couple of computers that you leave on
      24/7, and they draw around 3 amps total, then that's costing me about
      $36/month to run them.


      Paul




      ----------------------------------------------------------------
      "All right...initialize the GBL."
      "How do you do that, then?" Terry Pratchett
      "It...it means pull the great big lever." from "Hogfather"
      ----------------------------------------------------------------
    • Paul Archer
      ... You re correct, in that 6,640 watt hours would be 8.64 kwh. I had a typo in my original numbers. That should have been 86,400 watts. (120 watts * 24 hours
      Message 2 of 3 , Jul 6, 2006
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        12:04pm, ChasMauch@... wrote:

        >
        > In a message dated 7/6/06 10:41:24 A.M. Central Daylight Time, tigger@...
        > writes:
        >
        > 8,640 watt hours / month = 86.4 kwh / month
        > 86.4 kwh * $.14/kwh = $12 / month
        >
        >
        >
        > I thought a killowatt = 1,000 watts
        > so 8,640 watt hours = 8.64 kwh * $.14 = $1.20 month
        >

        You're correct, in that 6,640 watt hours would be 8.64 kwh.
        I had a typo in my original numbers. That should have been 86,400 watts.
        (120 watts * 24 hours * 30 days).

        Paul




        --------------------------------------------------------
        Never trust a computer you can't repair yourself.

        Paul's Corollary:
        Never trust a computer that's been repaired by its user.
        --------------------------------------------------------
      • blpasemann
        Don t forget about the P3 Kill-A-Watt meter. Very cool device to measure how much power something uses over time. I bought mine on Ebay last year and I love
        Message 3 of 3 , Jul 7, 2006
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          Don't forget about the P3 Kill-A-Watt meter. Very cool device to
          measure how much power something uses over time. I bought mine on
          Ebay last year and I love it. They don't make one for 220 yet.

          http://www.p3international.com/products/special/P4400/P4400-HG.html

          Thanx



          --- In hreg@yahoogroups.com, Paul Archer <tigger@...> wrote:
          >
          > I calculated this for my own use, and thought it would be helpful for
          > others.
          >
          > $.14/kwh (going rate in Houston)
          >
          >
          > 120 watts * 24 hours/day * 30 days/month = 8,640 watt hours / month
          > 8,640 watt hours / month = 86.4 kwh / month
          > 86.4 kwh * $.14/kwh = $12 / month
          >
          >
          >
          > So, if you have a 120V appliance/lamp/whatever that uses 120watts of
          power
          > (for instance, a light fixture with 2 60 watt bulbs), and you leave
          it on 24
          > hours a day, it'll cost you $12 a month.
          >
          > Since 120 watts at 120V is 1 amp, if you do measurements at your
          breaker box
          > (using a clamp-on amp meter, or "clampmeter"), you can see that each
          amp of
          > measurement (assuming it's for a constant, 24 hour/day load) will
          cost you
          > $12/month.
          >
          > You can extrapolate this, of course. For instance, if you have a
          light with
          > a 60 watt bulb, and you have it on for about 6 hours a day, it'll
          cost you
          > about $1.50 a month.
          > Or, if you're like me, and you have a couple of computers that you
          leave on
          > 24/7, and they draw around 3 amps total, then that's costing me about
          > $36/month to run them.
          >
          >
          > Paul
          >
          >
          >
          >
          > ----------------------------------------------------------------
          > "All right...initialize the GBL."
          > "How do you do that, then?" Terry Pratchett
          > "It...it means pull the great big lever." from "Hogfather"
          > ----------------------------------------------------------------
          >
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