Replies

I've been wondering for a while now: The price of incandescents have plummeted. With these prices, is it cheaper to purchase them and replace them more often than required with the CFLs? Is it now cheaper to use the traditional light bulbs, even if they give off more heat? Any thoughts are appreciated!

The price of incandescents have plummeted. With these prices, is it cheaper to purchase them and replace them more often than required with the CFLs?

The break even point is about a year. If you find an incandescent bulb on sale, it will only increase the break even point by maybe a month.

Is it now cheaper to use the traditional light bulbs, even if they give off more heat?

The general rule of thumb (subject to your electric utility rates) is that it costs about $100 to power a 100 watt incandescent light bulb continuously for a whole year.

I doubt you will keep a light bulb burning continuously, more likely only 8 hours a day, so it'd cost you $33 to power that 100 watt incandescent light bulb during a year's time.

The article doesn't really specify the efficiency of the new 100-watt-equivalent led light bulbs, except for this: "However, 60-watt bulbs are the big prize, since they're the most common. [snip] The energy savings that could be realized by replacing them with 10-watt LED bulbs is staggering." From this, it's suggested that they'll use 1/6 the energy for the same amount of light.

If that's true, then replacing your 100 watt incandescent light bulb ($0.32/bulb, $33/year @ 8hrs/day) with a 100-watt-equivalent led bulb ($50/bulb, $5.50/year @ 8hrs/day) works out like this: Assuming you have to replace the incandescent bulb once per year (mine don't seem to last very long), but that the LED bulb will last at least three years, this is the break down:

Year one running total:
Incandescent: $0.32 + $33 = $33.32
LED: $50 + $5.50 = $55.50

Year two running total:
Incandescent total: $33.32 + $0.32 + $33 = $66.64
LED total: $55.50 + $5.50 = $61.00

Year three running total:
Incandescent total: $66.64 + $0.32 + $33 = $133.28
LED total: $61.00 + $5.50 = $66.50

You can see you reach break-even in year two, and start to realize substantial savings in year three. That's a pretty good ROI, assuming the LED bulbs don't need to be replaced often.