Watt-Hour #atozchallenge


I’m including this because it was one of my great “duh!” moments. I mean, I’ve only been reading and paying electric bills for 40 years, you’d think I’d have understood this. Usually, when we’re talking your electric bill, you see “kilowatt hour,” or more frequently the abbreviation kwh, and you’re charged per kilowatt hour, right? Well, one day I got to thinking “what exactly is a kilowatt-hour?”

So, off to Wikipedia I went, and learned that a watt (named for James Watt, who helped develop the steam engine, not the former Secretary of the Interior) is one joule per second. Which told me nothing, since I was so bad at physics, and that it’s a measure of energy transfer. But I know my times and gazintas, as Jethro from The Beverly Hillbillies would call them, so I figured out that one watt-hour is 3600 joules, and thus a kilowatt-hour is 3,600,000 joules, or 3.6 megajoules. All of which told me as much as what a watt and a joule were.

So I looked up kilowatt-hour, which I should have done in the first place, and it told me that a kilowatt hour is the number of kilowatts times the number of hours. So, if I leave a 60-watt bulb burning for one hour, it uses 60 watt-hours, or 0.06 kilowatt-hours. At 10.7 cents per kilowatt-hour, that cost me 0.6 cents.

Now, here’s where all this comes in handy. I have a ceiling fan in my office which I have a tendency to leave running all the time. Mary sees this, turns it off, then reminds me to turn it off when I’m not using it. So I got to thinking: what would it cost if I left it on all the time? I did some research, and learned that the fan draws 75 watts of power. Leaving it on for 24 hours would consume 1.8 kwh, which would cost 19.3 cents. Leaving it on for a month would cost me $5.79, and $69.50 for the year. Not exactly nothing, but it’s not going to break the bank.

I showed these calculations to Mary, and she said, “turn the fan off when you’re not in your office.” So much for that argument.

Maybe I should buy stock in The Southern Company

11 thoughts on “Watt-Hour #atozchallenge

  1. Hah!
    We leave our bedroom ceiling fan on 24/7 because when we turn it off and turn it back on, it makes this faint squeaky whirring noise that keeps us awake. The Mister has oiled it as much as he can without disassembly, so we just leave it on.
    We got our annual report from IPL about how we’re doing with our power usage. We used to get FAIR because so many houses on the street were empty or lived in solely by one person. Now that some families moved in, we’re EXCELLENT. LOL go figure!


  2. Hahahahaha I think Mary won that subject! You’re too funny John, but thanks for the info. I think I’ll be just like Mary… hahaha! My dad use to tell me when I was little… and then I told my children and I heard my daughter saying to her boys… “When not in use… TURN OFF THE JUICE!!!! AHHHHHHH SUCH IS LIFE!


  3. Hi John – I don’t like leaving things on all the time … but wonder how much the actual turning off and on costs … rather than leaving it on – I leave it to you for your grey cells to churn over their wattages!! Cheers Hilary


  4. John,

    Remember, never argue with the wife, she’s always right even when you have a good basis for an argument don’t do it. lol We replaced all of our overhead lightbulbs with LED. The watts are very low on these things so we try to refrain from turning the lights off and on because that causes so much wear on the switch and could actually shorten the life of the LED which would defeat one of the purchases for us getting them to start with. The wattage cost is one part of the equation. You gotta think about what it’ll cost to repair switches or in your case the fan to replace if you wear it out flipping that switch on and off a lot.

    ~Curious as a Cathy
    A2Z iPad Art Sketch ‘W’ Water Glass


  5. You should listen to your wife! Also, don’t assume that when a plugged-in device is not in use, it couldn’t possibly be using electricity. Some devices that use chargers, still draw electricity even when switched off, e.g. laptops and cell phone chargers. Unplug if not in use, it saves a lot of electricity when added up.


  6. Hi John!
    This was enjoyable and informative! “Times and Gazintas” – ha! I have a habit or leaving my office radio on and now wonder how much I’m costing us.


  7. I was getting lost until the final bit about how much it costs you in a year. When you think about it, you add up the fan, the lights that we often having on when we don’t need to plus the computer, tv, etc…we spend a lot in usage. If we can turn things off when we leave the room, we could save quite a bit so…I agree with your wife:)


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