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Advantages And Disadvantages Of LEDs In The Home
LED Light Bulbs
LEDs Are The Latest Hot Green Topic
LEDs are the latest lighting technology and they have a few advantages over incandescent light bulbs and CFLs (compact fluorescent light bulbs). They also have some drawbacks, most of which are being improved upon constantly by manufacturers of LED light bulbs. However, they are seen by many to be the successor to both incandescent and CFL light bulbs as they use less energy than both types of bulbs and last even longer.
Advantages Of LEDs:
· LEDs use less energy than traditional incandescent and CFLs bulbs
· LEDs contain no mercury like CFLs do
· LEDs emit less heat than traditional incandescent and CFL bulbs
· LEDs last longer than traditional incandescent and CFL bulbs
· LEDs aren’t affected by cold temperatures like CFLs are
LED And CFL Bulb Side By Side
Disadvantages Of LEDs:
· LEDs are still expensive compared to other types of bulbs
· LEDs are sensitive to extreme heat
· LEDs are heavier than regular light bulbs
· LEDs are fairly directional in how they emit light
Now let’s looks at the advantages and disadvantages of LEDs in some greater detail…
Haitz's Law And LED Efficiency
LEDs Use Less Energy
The traditional incandescent light bulb wastes as much as 95% of the energy it consumes as heat. Thus, incandescent bulbs are extremely inefficient. CFLs are much better at converting the energy they consume into useful light. CFLs are about four times as efficient as compared to incandescent bulbs, wasting 80% of the energy they consume as heat. This is much better and that 80% might seem awfully high, but remember that CFLs use much less energy than an incandescent bulb to begin with and more of it is converted into light.
Now, LEDs typically use less energy than even CFLs and it is hard to pin an average efficiency on them. You see, LEDs are semiconductors, or electronic components. And their efficiency improves over time, doubling every 36 months. This is similar to Moore’s Law, and LEDs have their own Moore’s Law, termed Haitz’s Law. This law has been consistent since the 1960s when LEDs were simply electronic indicators (power or status lights). In the past few years, LED light bulbs approached the efficiency of CFLs. This means that they’re currently surpassing the efficiency of CFLs and as long as Haitz’s Law holds, LED bulbs will be twice as efficient as CFLs within several months.
Cost Savings Of An LED Bulb
Utilitech LED (7.5 watt)
CFL (13 Watt)
Incandescent (60 Watt)
Hours On Per Day
Cost Of Electricity
$0.11 per kwh
$0.11 per kwh
$0.11 per kwh
Yearly Cost For Energy
Savings Over Incandescent Bulb (Per Year)
Number Of Bulbs To Equal The Lifetime Of An LED
Cost Per Bulb (Average In Some Cases)
Bulb Costs Over Lifetime Of LED
LEDs Contain No Mercury
Everyone knows that mercury is hazardous to human health. And most people also know that CFLs use mercury in order to create light. It may be a small amount, but it makes CFLs risky to use around children or in lamps that may be easily knocked over. It also complicates the recycling process of burned out CFLs. Recycling centers currently only accept unbroken CFLs. Remember though that a typical tuna sandwich has more mercury in it than a single CFL does, but mercury is not good for human health in any quantity, great or small. However, people eat tuna pretty regularly, and I can’t recall ever hearing of anyone suffering from mercury poisoning related to that.
LEDs contain no mercury as they’re a solid-state electronic device and contain no moving parts, gasses or heavy metals like mercury to make them work. Thus they’re safer than CFLs if they will be used around children or in lamps that are at risk for being knocked over and broken. And because of this, LEDs can be taken in and recycled, broken or unbroken.
LEDs Emit Less Heat
Since LEDs are so efficient and becoming more efficient all the time, less and less of the energy they consume is wasted as heat and more is turned into useful light. This is extremely advantageous in warmer climates, especially during the summer. Less heat is being generated by lighting sources in the home which means less work for the air conditioner or HVAC system to handle, making the indoor climate of a home more comfortable and saving more energy by reducing cooling demand.
While LEDs still emit some amount of heat, it is still far less than the heat emitted by incandescent light bulbs and this also makes them safer around small children. Little fingers like to explore and touch, leaving them at risk to burn themselves on hot light bulbs that might be within their reach. LEDs are warm, but not to the point to burn skin.
LED Bulb Longevity
LEDs Last Longer
We know that LEDs are solid-state electronic devices and that they have no moving parts or gasses. Thus, LEDs can be expected to last many times longer than incandescent and CFL bulbs. Most manufacturers claim that their bulbs will outlast 25 incandescent bulbs or 5 CFLs. This makes LEDs ideal for replacing bulbs in hard to reach areas and fixtures. Thus, LEDs will likely not have to be changed for around 20 years, if not more, depending on usage patterns.
You see…LEDs don’t burn out like regular incandescent light bulbs or CFLs. The typical failure mode for LEDs is to slowly dim over time, fading to 70% of their original brightness by the end of their expected lifetime. That is, they don't fail outright once they've faded, that is simply the point at which they should be replaced, even though they still work.
LEDs And Cold Weather
LEDs Aren't Affected By Cold Temperatures
Well, actually they are, but cold temperatures can have a positive impact on their life expectancy, and depending on the temperature it can increase the amount of light output…to a point. This makes LEDs suitable for use in refrigerators and freezers and supermarkets have found these to be a great investment and have realized that they can save a great deal of energy and human capital from not having to replace burned out fluorescent tube lights.
Speaking of fluorescent lights and cold temperatures, if you’ve ever turned on a CFL that was installed in an outdoors fixture on a cold winter night, you know that CFLs are extremely dim at cold temperatures and can take quite a while to warm up to full brightness if at all. LEDs have no warm-up period like CFLs and turn on at full brightness regardless of how cold it might be. This makes them suitable for use outdoors in colder climates where full brightness is expected and necessary for safety.
LEDs Are Still More Expensive Than Other Bulbs
The cost of LEDs has fallen rapidly over the last few years and continues to do so. However, individual bulbs still cost more than a single incandescent or CFL bulb. This makes most consumers pass them up when purchasing new bulbs. Their high cost makes it expensive to replace many bulbs in a home. However, their long lifetimes and decreased energy consumption more than offsets the higher initial cost over time.
Since most LED bulbs are claimed to last as long as 25 incandescent bulbs and 5 CFLs, the cost of purchasing individual bulbs of either type to match the life expectancy of an LED bulb can be considered a savings. This offsets the cost of the bulb, allowing the reduced energy consumption to pay for the rest of the bulb over time and eventually have a positive rate of return as an investment.
LEDs And Heat
LEDs Are Sensitive To Extreme Heat
If you’ve ever seen or handled a retail LED bulb that is marketed as a replacement for 40 and 60 watt incandescent bulbs, then you may have noticed that most of the LED bulb is comprised of some type of metal, typically aluminum. The reason for this is to dissipate the heat generated by the bulb. This heat, if it were allowed to build up around the bulb and wasn’t dissipated effectively, the LED bulb’s life expectancy would be cut very short and it could potentially suffer a catastrophic failure due to warping of the circuit board that the individual LEDs are mounted to.
The heatsinks that are built into the body of LED light bulbs are very effective at keeping the bulb cool and within its operating temperature range. However, there are light fixtures that LEDs aren’t suitable for use in, such as recessed ceiling or sealed fixtures. Even with a heatsink, LED bulbs installed in such fixtures can over heat as the heat dissipated by the bulb has nowhere to go except into the space immediately around the bulb. This can lead to the problems with heat mentioned above. So, LEDs are great for lamps and fixtures that are unsealed and have good airflow.
LEDs Are Heavier Than Other Bulbs
The heatsinks that LED bulbs use to dissipate the heat they generate add extra weight to the bulb. This makes them heavier than incandescent and most CFL bulbs. Thus, some lamps, like bendable desk lamps or other lamps with bendable or adjustable parts, can be affected by this increased weight. This can make them either droop or fall over from the weight (in the case of small desk lamps) although this is only likely to happen with lamps made from cheap parts or with less sturdy flexible lamp necks. So until LEDs become even more efficient and generate less heat and are able to dissipate it with smaller and thus lighter heatsinks, they are much more suited to sturdier lamps that aren’t flexible or adjustable.
Light Distribution Of LEDs and CFLs
LEDs Are Fairly Directional
The majority of LEDs emit light in a fairly consistent pattern…in a beam straight out from the top of the bulb. Early LED bulbs emitted light very similar to how a flashlight does, in a beam that didn’t spread very well. This made most LED bulbs suitable for use as spotlights or decorative accent lighting only and little else. However, manufacturers have improved upon this greatly, tweaking the design of their LED bulbs in order to make them more similar to incandescent and CFL bulbs in how they emit light. This has improved them greatly, as light can be emitted in a more broad range.
In a typical table lamp, older LEDs bulbs would emit most of their light towards the top of the lamp and none below. Newer bulbs emit light more evenly with more of the light emitted being directed down or towards the base of the bulb as is typical. Changes in bulb design, a continuing process improves upon this with every generation of LED bulb.
Will LEDs Ever Be As Good As An Incandescent Bulb?
For most intents and purposes, LEDs are already great replacements for incandescent bulbs in several applications in the home. Night lights can be replaced with cheap low power LED bulbs that will last years and years. Reading, closet, appliances (like refrigerators), and table lamps are good candidates for using higher wattage LED bulbs in. For LEDs to truly gain market share, the disadvantages above will have to be greatly diminished, but with the impending phase out of the incandescent bulb, manufacturers will be investing heavily into research and development of better bulbs. And with Haitz’s Law on their side, future LED bulbs will generate even less heat and more light for the amount of energy they consume, leading to brighter bulbs that consume even less energy.