Comparing Light Bulb Costs – energy saving bulbs versus normal?

How much does it cost to run a normal 100W light bulb? Per hour and the whole life of the bulb (please specify the life span you are using).

How much does it cost to run a 25W (equivalent to 100W of a normal bulb) energy saving light bulb? Per hour and the whole life of the bulb (please specify the life span you are using).

Please use the rate of 9.8 cents/Kw-hour.

If you have any other ways to compare these two bulbs in terms of money, please do share.

2 comments

    • MT C on April 23, 2010 at 12:42 pm
    • Reply
    The easiest way to do this is to check the boxes for average longevity and comparative cost. They are usually both listed.

    If you must do the calculations, use the average life in hours divided by 1,000 multiplied by the stated wattage times $.098

    • T C on April 23, 2010 at 12:45 pm
    • Reply
    kw-hour is kilo-watt each hour

    100 watt will use .98 or 98% of a penny or $00.098 each hour

    25 watt will use .25 or 25% of a penny or $00.025 each hour

    no bulb lasts as long as the life is, so comparison is a guess

    say each bulb lasts 6000 hours one costs 40 cents, the other costs $2.50

    100 watts = .098 x 6000 = $58.8 25watts = .025 x 6000 = $15.0

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