Question

Light emitting diodes (LED) light bulbs have become required in recent years, but do they make financial sense? Suppose a typical 60-watt incandescent light bulb costs $.37 and lasts 1,000 hours. A 15-watt LED, which provides the same light, costs $3.00 and lasts for 12,000 hours. A kilowatt-hour of electricity costs $.113. A kilowatt-hour is 1,000 watts for 1 hour. If you require a return of 10 percent and use a light fixture 500 hours per year, what is the equivalent annual cost of each light bulb?

Answer 1

Answer:

Annual wattage cost of 60 watts is $3.729

Annual LED cost of 60 watts is $0.185

total annual cost = $3.914

Annual wattage cost of 15 watts is $0.935

Annual LED cost of 15 watts is $0.125

total annual cost = $1.06

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Explanation:

For the cost of LED and durability

it is require to use a light fixture 500 hours per year

60-watt incandescent light bulb costs $.37 and lasts 1,000 hours. that mean, its last for 2years before buying a new one.

And for a 15-watt LED,  costs $3.00 and lasts for 12,000 hours, thats means it will last for 24 years before purchase of another.

assuming, will are using the 60watts for 24years, a cost of  $.37*12times = $4.44 will be use for buying.

therefore, a 15 watts LED is more cheaper.

For the current charges of LED

for 60watts

if A kilowatt-hour of electricity costs $.113 =

1000 watts = 1hour = $0.113

60 watts  = 1hour  = (60*0.133/1000) = $0.0068

it is said that, the consumption is for 500 hour per year.

therefore, 60watts used per year = 500*0.0068 = $3.39

return of 10% =0.339.

total cost of watts for 500hr for a year = 3.39+0.339 = $3.729

Annual wattage cost of 60 watts is $3.729

Annual LED cost of 60 watts ($0.37/2year) is $0.185

total annual cost = $3.914

for 15 watts

if A kilowatt-hour of electricity costs $.113 =

1000 watts = 1hour = $0.113

15 watts  = 1hour  = (15*0.133/1000) = $0.0017

it is said that, the consumption is for 500 hour per year.

therefore, 15 watts used per year = 500*0.0017 = $0.85

return of 10% =0.085.

total cost of watts for 500hr for a year = 0.85+0.085 = $0.935

Annual wattage cost of 15 watts is $0.935

Annual LED cost of 15 watts ($3/24 years) is $0.125

total annual cost = $1.06