How much power am I really wasting

June 23, 2011 - By: Eugene Breacan

Am I wasting a lot of power by leaving a lamp on all the time? My girlfriend is pretty adamant about me turning off a lamp in my living room, which I have grown accustom to just leaving on all the time. When we leave the house, or turn in for the night it's a question I've come to expect, "Are you going to turn the light off?". I always chuckle to myself because between the two of us, she is most definitely the more frugal minded, I don't give the light a second thought.

Curiosity has started to get the best of me though, wondering how much power I really am wasting, which in my mind grew into something even larger and became "what else could I power with the energy I've been wasting".

How much energy have I wasted?
Lets start with the first part of the question, this leads us to a formula to calculate electrical usage which is measured in kilowatt-hours. To make this article a bit more readable, I have placed all my calculations and formulas at the end, just in case your interested in determining your own usage or you can use our appliance cost calculator to determine your usage and cost. I calculated in a 24 hour period that the light bulb (a 13 watt energy efficient CFL) uses 0.312 kWh (kilowatt hours) which means in the past 120 days I have used 37.44 kWh.

Note: I used 120 days in my calculations because I moved into my new home roughly 4 months ago.

I determined I really only need this lamp for about 2 hours a day which means after applying the same formulas to a 2 hour time period, that of the original 37.44 kWh I have wasted 34.32 kWh. If you extrapolate these calculations out a bit further I am wasting 102.96 kWh per year.

What could I power with that?
I have to admit I was pretty impressed with the performance of the energy efficient CFL light bulb. Over the course of a year, being used 24 hours per day, it only wastes in my scenario 102 kWh. After looking at these numbers I started to think, "well that's great but what am I really wasting?". So I give you my list of "what I can do with 102 kWh".

I can:

• run a regular 60 watt light bulb for roughly 71 days.
• power a 17 LCD computer monitor for 106 days.
• watch a 50” plasma TV for 12.5 days.
• run an xbox 360 for 31 days.
• run my Nintendo Wii for 325 days. (yes, it uses that much less power than the xbox. - source)
• keep my 48” ceiling fan on for 57 days.
• keep my air conditioner running for roughly 1 day and 6 hours.

Do I think I'm wasting energy? Yes, of course I am, regardless of how little it is, (thanks to the CFL bulb). So, the next time my girlfriend asks me to turn off the light I will ponder these numbers thinking to myself does it really matter, and then if I know whats good for me, I'll go turn off the lamp.

Formula:
Wattage / 1000 x hours used
(13 watt bulb / 1000) x 24 hours = 0.312 kWh
0.312 x 120 days = 37.44 kWh

Appliance wattage - source

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