Friday, June 6, 2014

The Light Bulb Dilemma

I hate waste and I hate high electric bills.  I know if I replace burned out light bulbs with more efficient bulbs, I will be reducing waste by using less electricity and will be paying lower electric bills.

Every so often, though, the question has popped into my head whether I should throw out perfectly good incandescent bulbs and replace them right away instead of waiting for them to burn out.  That seems like a needless waste.  On the other hand, would the reduction in electricity make up for the fact that I have discarded a working light bulb? 

Knowing that compact fluorescent light bulbs (CFL) are more efficient and last longer but cost more than the traditional incandescent and that the newer LED bulbs are even more efficient, last even longer but are even more expensive is not enough to decide.  I needed numbers.  So I went to the National Resource Defense Council website for answers.  It has tables showing the cost of a new bulb, its life expectancy and its average energy usage.

A 60-watt bulb, for example, costs about half a dollar, but uses about $8 of energy per year and lasts only about one year.  The equivalent CFL costs about $3 by the table (I just bought 3 for $6 so the price continues to come down.) and uses $1.74 of electricity per year.  If I throw out an incandescent bulb the waste is less than fifty cents, since I’ve already partially used it up.  I recoup the cost of the new bulb (on average) in less than 4 months ($2.00 cost divided by the expected energy saving, $8 - $1.74 = $6.26, equals less than one-third of a year).  Sounds like a good decision even if the CFL didn’t last as long as they claim, especially considering that continuing to burn the old bulb is costing considerably more.  (LED prices for the same amount of light have dropped too, but taking the next step from CFL to LED is more difficult to justify since the energy savings is only 40 cents per year.)

Now I know the answer to my occasional question –another victory for a little research and critical thinking!

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