Tuesday, January 11, 2011

Easy Energy Cost Calculator

When i'm doing energy assessments, often people like to know how much energy different items use. To save on mental arithmetic, i put this little table together to work out the annual cost (using local electricity prices).

Standby power - If a stereo is using 5 watts (all day) on standby. How much does that cost? $9/year.

Light bulbs - How much do the new ones save? Let's find out. 75W bulb, 5hrs a night, $29. Equivalent CFL (15W) for 5hrs, $6. Saving of $23.

Computers - A laptop consuming 40W for 5 hours a day costs $16 a year to run. (Using the 20W figure and doubling it.)

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