GoGreen Mailbag: LED Lighting
From time to time, we receive several inquiries about the same topic. We’ll try to address those topics in a brief, practical way in this ongoing series we call the Go Green Mailbag. This time, we discuss LED lighting.
What are LED bulbs, and how do they work?
LED stands for Light-Emitting Diode. A diode is a semiconductor with two terminals. When electrons move from one side of the diode to the other, they release energy, in the form of light. The color of the light emitted is based on the chemicals that have been applied to the diode, so LEDs can be made in a variety of colors, including warm colors like the light emitted by traditional incandescent bulbs.
For more on the science behind how LEDs work, check out this article from the Union of Concerned Scientists.
How are LED bulbs different from incandescent or compact fluorescent bulbs?
Incandescent bulbs produce light by running an electric current through a filament made of a resistant metal. This causes the filament to heat up and ultimately produce light. Incandescent bulbs emit up to 90% of their energy as heat, which is why they are inefficient lighting choices.
Compact fluorescent lamp (CFL) bulbs run electric current through a tube containing gases that produce light when exposed to electricity. However, CFLs also take a few minutes to reach full brightness as the gases become excited and burn out more quickly when turned on and off frequently. They also contain small amounts of mercury, which is essential to their light production, but harmful to humans.
Additionally, CFLs release the largest portion of their energy (80%) as heat, but the energy used to light them is significantly-less (only 25%-35% of the energy used to light an incandescent bulb, according to the Department of Energy). Because they require so much less energy to emit light, CFLs are still significantly more efficient than incandescent bulbs.
LEDs are fully-dimmable, light instantly, do not suffer ill effects from frequent on/off cycling.
Wow! What are some other benefits of LEDs?
LEDs have incredibly long lifespans, outlasting both incandescents (by 30 times!) and CFLs. The Department of Energy estimates an incandescent bulb’s lifespan at about 1,000 hours of use, a CFL’s at 8,000-10,000 hours, and an LED’s at a whopping 30,000 hours of use!
LEDs don’t contain mercury like CFLs do, so there’s no need for a special cleanup procedure if one breaks.
LEDs are durable. Because there are no moving parts and LEDs are self-contained, they’re resistant to shock, vibration, and moisture. In addition, they maintain performance at low temperatures, making them excellent for year-round outdoor lighting.
Everyone says that LEDs are better for the environment, but how much of a difference does changing my lightbulbs really make?
LEDs use about the same amount of energy as CFLs but emit more of it as light as opposed to heat. In comparison to incandescents, LEDs use significantly-less energy. To emit the same amount of light as a 60 watt incandescent bulb, LEDs use just 12 watts (or 20% of the incandescent’s use). The Department of Energy estimates that by 2035, annual savings from LEDs will be equivalent to the total annual energy consumed by 45 million US homes today. Not only that, but the Union of Concerned Scientists estimates that each incandescent bulb you replace with an LED bulb keeps 87 pounds of heat-trapping carbon dioxide out of the atmosphere.
Are LEDs more expensive? Where can I buy them?
Traditionally, LEDs have had a higher up-front cost than CFL and incandescent bulbs. This is still generally the case, but they are constantly getting cheaper as they become more popular. Now you can purchase a standard A-Type bulb from many retailers for around $5.00. Remember that in the long run, LEDs more than pay for themselves. According to the Union of Concerned Scientists, a 12-watt LED bulb costs approximately $1.75 to operate for four hours per day for a year (assuming electric costs of 10 cents/kWh).
Most stores that sell lightbulbs now carry LEDs.
If you are looking for a great deal on LED bulbs, EcoBuilding Bargains sells LEDs of various shapes and sizes for a fraction of the usual retail cost. If you are not sure what type of LED bulb would work best in your space, ENERGY STAR has compiled this useful chart.
We hope you found this post helpful and informative. Stay tuned for future installments of the Go Green Mailbag!