LED Lighting Is Cheaper: Mathematical Proof of the Advantages of LED Bulbs
An LED spotlight.
By Mcapdevila [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
Are LED Bulbs Cheaper or More Expensive Than Other Types?
When comparing light bulbs' prices, LED options may seem expensive. For example, you can often buy a 60-watt incandescent light bulb for less than 1 dollar. The fluorescent (CFL) equivalent will likely cost you around 2 dollars; if you go for LED, you will pay 4 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 mathematical proof.
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?
How Much Will It Cost to Power Different Types of Bulbs?
| Type of Bulb | Power Consumption | kWh in 1,000 Hours | Dollars Spent |
|---|---|---|---|
Incandescent | 60 W | 60 kWh | $9.00 |
Compact Fluorescent | 15 W | 15 kWh | $2.25 |
LED | 10 W | 10 kWh | $1.50 |
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.
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 the 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 let's calculate 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).
Comparative Costs of Different Types of Bulbs for 1,000 Hours of Light
| Type of Bulb | Retail Price | Service Life (Hours) | Cost of 1,000 Hours |
|---|---|---|---|
Incandescent | $1.00 | 1,000 | $1.00 |
Compact Fluorescent | $2.00 | 10,000 | $0.20 |
LED | $4.00 | 25,000 | $0.16 |
Despite its higher retail price, the LED bulb also wins in terms of operating hours offered for every dollar spent.
Various types of LED bulbs.
Geoffrey.landis at English Wikipedia [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via W
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, and
- 32% cheaper than fluorescent lighting.
