Will LED bulb pay for itself?

When we talk about something saves, a common phrase we would often use is: "It will pay for itself.", Can we use the same phrase on LED bulbs? Let's start with the math.

 A 60 watt equivalent LED bulb right now retails for $12.75 and uses about 10W of power.

A common competitor 60 watt equivalent CFL bulb cost much than that (often less than $1 when with rebate) and use about 14W of power.

If we run one light bulb 6 hours a day, for 8 years it would have run for 17520 hours.

 

10 Watt LED bulb would consume totally 175.2 kw-hrs, which cost $29.78

14 watt CFL bulb would consume totally 245.28 kw-hrs, which cost $41.7

            (based on 17 cents per kw-hrs PG&E average residential rate)

The $12 difference in electricity cost would just pay for the LED bulb; but it took 8 years.
Of course, if that light bulb is light up 24/7, it would be faster, but still needs 2 years,

The real energy saving of using LED light is from its directionallight source characteristic when with right application ... 

Eg.  Our world Lamp 30 Watt LED shoplight (uses 32watt power) has light intensity compare to traditional shoplight with two 4' T8 tubes, that's roughly 64 Watt power usage.   Click here to see our shoplight compare to LED bulbs.

For the same case of 8 years.

Traditional shoplight would use 1121.3 kw-hr, that's $190.6 electricity bill

World Lamp LED shoplight would use 560.6 kw-hr, that's $95.3 in electricity bill, 

The cost saving is more than two World Lamps ....