Are LED Lights Worth It?

Everyone is trying to save money and energy today. The first thing you are told to do is replace incandescent lights with new technology lights. This saves energy but does it save you money? I want to take a few minutes to run the numbers on the new and not so new lights out there. This won't be an in-depth summary on lighting just a check to see if the new lights are worth the upfront expense.
The Assumptions
I will use 10 cents a Kilowatt Hour for the cost of electricity (0.10/KWH).
I will assume 4,000 hours of use a year.  This is about average for a retail or restaurant occupancy.
I am using a 60 watt incandescent light as the basis of the calculation, so my comparison lights will have 800 lumens plus or minus.
I will look at the prices on a 1 year, 5 year and 10 year scale.
The cost of money is 7%.  This will be important in the comparison section because once you buy the lights you don't have that money left to spend on something else or earn you money.  Below will be an annual cost of ownership, this is the price of the bulb amortized at 7% over the life span of the bulb divided by 4,000 hour per year.

Incandescent Lights
For the purposes of this exercise I will assume that incandescent lights are free.  A quick price check shows I can get 8 packs for less than 2 dollars so I am rounding this cost to zero.
60 watts x 4,000 hours = 240,000 watts (Watts per year).
240 KWH x $0.10 = $24.00 per year to run the incandescent bulb.
Annual cost of Ownership = $0.00.  (Since the bulb cost nothing the cost to own the bulb is also $0.00.)

Fluorescent
I am using a 13 watt compact fluorescent they put out about 900 lumens and last about 8,000 hours and cost about $10.00.
13 watts x 4,000 hours = 52,000 watts (Watts per year)
52 KWH x $0.10 = $5.20 per year to run the fluorescent bulb.
Annual cost of Ownership = $5.40 ($10.00 at 7% for 2 years)

LED
LED lights are a little more complex than the others. I am using a LED based light with similar light output as the above 2 lights, 13 watts, 900 lumens and 50,000 hour life.  The price I am using is $75.00.  You can find cheaper lights with longer life spans but the color of the light is not compare able to the others.
13 watts x 4,000 hours = 52,000 watts (Watts per year)
52 KWH x $0.10 = $5.20 per year to run the LED bulb.
Annual cost of Ownership = $9.00 ($75.00 at 7% for 12.5 years)

The Comparison
Incandescent = 1 year $24.00 - 5 year $120.00 - 10 year $240.00
Fluorescent = 1 year $10.60 - 5 year $53.00 - 10 year $106.00
LED = 1 year $14.20 - 5 year $71.00 - 10 year $142.00

Conclusion
LED prices would have to drop to $45.00 to be even with CFL.

Burt Andrews is an Architect with over 20 years of experience in designing restaurants and retail stores. You can read more of his restaurant ideas and about restaurant architecture at his blog archisaur.us. He is a principal at Larson and Darby Group in charge of the St. Charles, IL office.