LED Lighting is Actually Cheaper to Own: Mathematical Proof

Updated on May 10, 2016
An LED spotlight.
An LED spotlight. | Source

The Misconception that LED Bulbs are Expensive

When you compare the prices of light bulbs, LED options may seem expensive. For example, you can now buy a 60-watt incandescent light bulb for probably less than a dollar. The CFL equivalent will likely cost you around two dollars, and if you go for LED you will probably pay four dollars, give or take.

It is true that the upfront cost of an LED bulb is higher, but there are two factors that actually make it cheaper to own:

  • A long service life
  • A very low power consumption

These two factors make LED the cheapest alternative, and this article will provide a mathematical proof of it.

LED Advantage #1: Energy Savings

Incandescent bulbs may be cheap, but they are extremely inefficient. For example, a 60-watt bulb can be replaced with a 15-watt CFL or a 10-watt LED bulb, and still achieve the same lighting effect. In other words, LED technology saves more than 80% of the energy compared with incandescent lighting, and around 33% of the energy compared with fluorescent lighting.

Let's assume you live in a location where the cost of electricity is $0.15 per kilowatt-hour. How much would you spend in 1,000 hours of operation with each light bulb?

Type of Bulb
Power Consumption
kWh in 1,000 Hours
Dollars Spent
60 W
60 kWh
Compact Fluorescent
15 W
15 kWh
10 W
10 kWh

This table clearly shows that LED lighting is the superior technology in terms of energy expenses. Now let's compare the service life of all three alternatives.

Various types of LED bulbs.
Various types of LED bulbs. | Source

LED Advantage #2: Service Life

By comparing all three types of light bulbs based on the retail price only, it may seem that LED bulbs are more expensive to own:

  • 60-Watt Incandescent Bulb = $1.00
  • Equivalent 15-Watt Compact Fluorescent Bulb = $2.00
  • Equivalent 10-Watt LED Bulb = $4.00

However, to be fair, we also have to compare the rated service life of each alternative. The service life of a bulb may change by manufacturer, but the following are some typical values:

  • Incandescent Bulb = 1,000 hours
  • Compact Fluorescent Bulb = 10,000 hours
  • LED Bulb = 25,000 hours

Let's create another table, but this time calculating how much you have to pay to get 1,000 hours of light bulb service life (the previous table calculated the operating cost, this one is the capital cost).

Type of Bulb
Retail Price
Service Life (Hours)
Cost of 1,000 Hours
Compact Fluorescent

Despite its higher retail price, the LED bulb also wins in terms of operating hours offered for every dollar spent.

Total Costs of Ownership

Adding the results of both tables, we can calculate the cost of 1,000 hours of lighting with each technology:

  • Incandescent = $9.00 + $1.00 = $10.00
  • Fluorescent = $2.25 + $0.20 = $2.45
  • LED = $1.50 + $0.16 = $1.66

The LED bulb is the winner, hands down. The total cost of getting 1,000 hours of lighting with LED technology is:

  • 83% cheaper than incandescent lighting.
  • 32% cheaper than fluorescent lighting.

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