Update on LEDs
I helped "green" the houses of my sister and a couple friends. It's been a few years since I greened my own place, and there's been a huge improvement in a lot of lighting technologies. LEDs have become very reasonably priced, especially considering how efficient they are and how long they last.
First off, two things to look closely at are color and lumens. LEDs are typically a very pure white. Like purified water, we're not used to consuming it in its purest form. Most people prefer a softer light. Color is measured in Kelvin or K. Higher numbers (4000-6000K) are closer to sunlight and typically aren't used unless you need a pure white light. Most households use a 2700K (the "softest" light, most typically used for gentle lighting like bedrooms and living rooms) or 3000K (a "warm" white, slightly brighter used in kitchens and bathrooms). LEDs try to get close to a soft light but since LEDs run white, they may be a bit brighter than you're used to. The difference between 2700K and 3000K may be more subtle than their incandescent versions.
The other thing to look closely at is lumens. Lumens is the measurement of a bulb's brightness. Many bulbs (both CFL and LED) use "watt equivalents" to give the user an idea of what the rough equivalent incandescent bulb would be. The issue is that this number is subjective. Even amongst incandescent lights, two bulbs with the same wattage can have a different lumens. Some 40 watt bulbs can be as low as 300 lumens or as high as 500. Because the brighter a bulb is, the more LEDs have to go into it, that means it costs more to manufacture. So some manufacturers will try and pass a lower brightness bulb as a higher wattage equivalent. Look at the lumens and you can compare apples and apples.
LED have some significant advantages over CFLs. For one, they are more likely to be dimmable, or at least not be that much more expensive for the dimmable version. Some may have issues with older dimmers, but modern dimmers work (those manufactured in the last 10 years) better, or best yet, buy a dimmer specifically made for LEDs. (They'll work better with dimmable CFLs as well. We had issues with dimmable CFLs until we put it on a dimmer built for such.)
Secondly, LEDs are instant on and instantly bright. There is no waiting time for it to get bright. There may be the slightest pause when first turning on, but it's typically less than a second.
Unlike CFLs, they also work in very cold environments. That can make them a good power-efficient substitute for an outdoor light in extremely cold environments. (Most CFLs will start down to about 0 degrees and may take longer to get bright but will work). They don't, however, work in extremely hot environments. Many are not rated for unventilated enclosures. Check the label to see if it's rated for enclosures first before using in such.
I've noticed that the light from one CFL to another isn't always consistent, even when new, so when using them side by side, slight differences may be noticeable. LEDs work better if you need absolute consistency (within a brand and model, of course).
They are the most efficient technology as well. They're typically 10-25% more efficient than CFLs, and up to 83% more efficient than incandescents. They also last the longest, anywhere from 25,000-50,000 hours. That's 22-45 years assuming 3 hours a day, but in applications where they are on 8-12 hours a day (such as offices), that's 6-15 years. Cities are now using them for street lighting because high-pressure sodium lights have to be replaced every 18 months, whereas LEDs are only every 7 years, vastly reducing maintenance time as well as saving money in energy costs.
They are also mercury free. Modern CFLs have an absolute minute amount of them (typically 2-4mg or less), but still some people are concerned about them, should they be disposed of improperly.
The other area that is LEDs individually tend to be quite directional. They can be diffused with smoked glass and such, but this can actually be an advantage. For that reason, LEDs tend to work well for flood and spot lighting. For another reason, flood and spot lights tend to be expensive on their own. A spot incandescent or halogen light bulb alone can cost $4-9, and it'll only last about 1,000-2,000 hours, meaning you'll have to replace it in a year with normal use. Between the bulb costs and the electricity savings, LED flood lights can pay for themselves within about a year. I've also noticed that when replacing directional bulbs (like flood lights), you don't necessarily need as many lumens to achieve the same lighting, because the directionality of LEDs mean fewer lumens more concentrated equal the same lighting effect. Buy one to check if it'll work in your application before replacing all of them.
Finally, LEDs tend to work well in the presence of vibration. Both incandescent (particularly those not rated for "rough duty") and CFLs work poorly in areas with fans (like an exhaust fan/light in a bathroom) or vibrations like garage doors.
That's not to say they don't have downsides. The cost can be quite high. Some energy companies subsidize them to encourage people to switch, but without subsidies, they can retail for $10-20 and up. The good news is hopefully you'll never need to replace them. They also don't work in all dimmers, particularly older ones, like those manufactured over 10 years ago.
Also, they tend to be sensitive to high heat. Some people have had issues with using flood lights in insulated canisters or in enclosures. Check if they're enclosure safe before using in such an application.
In most cases, if you can use a CFL, use a CFL. Particularly in more marginal applications (rooms that are not on often, like closets), your break-even point is going to be in the years, not months. Some people like the lights of an LED better, but there's clearly an additional cost to them. With some bulbs like A19s, the cost may not be that much more expensive to warrant the advantages (instant on, dimmable, better quality light), and obviously the more you use the lights, the quicker the payback will be. But if the benefits of an LED get you to use them instead of an incandescent, it's definitely worth checking out.
First off, two things to look closely at are color and lumens. LEDs are typically a very pure white. Like purified water, we're not used to consuming it in its purest form. Most people prefer a softer light. Color is measured in Kelvin or K. Higher numbers (4000-6000K) are closer to sunlight and typically aren't used unless you need a pure white light. Most households use a 2700K (the "softest" light, most typically used for gentle lighting like bedrooms and living rooms) or 3000K (a "warm" white, slightly brighter used in kitchens and bathrooms). LEDs try to get close to a soft light but since LEDs run white, they may be a bit brighter than you're used to. The difference between 2700K and 3000K may be more subtle than their incandescent versions.
The other thing to look closely at is lumens. Lumens is the measurement of a bulb's brightness. Many bulbs (both CFL and LED) use "watt equivalents" to give the user an idea of what the rough equivalent incandescent bulb would be. The issue is that this number is subjective. Even amongst incandescent lights, two bulbs with the same wattage can have a different lumens. Some 40 watt bulbs can be as low as 300 lumens or as high as 500. Because the brighter a bulb is, the more LEDs have to go into it, that means it costs more to manufacture. So some manufacturers will try and pass a lower brightness bulb as a higher wattage equivalent. Look at the lumens and you can compare apples and apples.
LED have some significant advantages over CFLs. For one, they are more likely to be dimmable, or at least not be that much more expensive for the dimmable version. Some may have issues with older dimmers, but modern dimmers work (those manufactured in the last 10 years) better, or best yet, buy a dimmer specifically made for LEDs. (They'll work better with dimmable CFLs as well. We had issues with dimmable CFLs until we put it on a dimmer built for such.)
Secondly, LEDs are instant on and instantly bright. There is no waiting time for it to get bright. There may be the slightest pause when first turning on, but it's typically less than a second.
Unlike CFLs, they also work in very cold environments. That can make them a good power-efficient substitute for an outdoor light in extremely cold environments. (Most CFLs will start down to about 0 degrees and may take longer to get bright but will work). They don't, however, work in extremely hot environments. Many are not rated for unventilated enclosures. Check the label to see if it's rated for enclosures first before using in such.
I've noticed that the light from one CFL to another isn't always consistent, even when new, so when using them side by side, slight differences may be noticeable. LEDs work better if you need absolute consistency (within a brand and model, of course).
They are the most efficient technology as well. They're typically 10-25% more efficient than CFLs, and up to 83% more efficient than incandescents. They also last the longest, anywhere from 25,000-50,000 hours. That's 22-45 years assuming 3 hours a day, but in applications where they are on 8-12 hours a day (such as offices), that's 6-15 years. Cities are now using them for street lighting because high-pressure sodium lights have to be replaced every 18 months, whereas LEDs are only every 7 years, vastly reducing maintenance time as well as saving money in energy costs.
They are also mercury free. Modern CFLs have an absolute minute amount of them (typically 2-4mg or less), but still some people are concerned about them, should they be disposed of improperly.
The other area that is LEDs individually tend to be quite directional. They can be diffused with smoked glass and such, but this can actually be an advantage. For that reason, LEDs tend to work well for flood and spot lighting. For another reason, flood and spot lights tend to be expensive on their own. A spot incandescent or halogen light bulb alone can cost $4-9, and it'll only last about 1,000-2,000 hours, meaning you'll have to replace it in a year with normal use. Between the bulb costs and the electricity savings, LED flood lights can pay for themselves within about a year. I've also noticed that when replacing directional bulbs (like flood lights), you don't necessarily need as many lumens to achieve the same lighting, because the directionality of LEDs mean fewer lumens more concentrated equal the same lighting effect. Buy one to check if it'll work in your application before replacing all of them.
Finally, LEDs tend to work well in the presence of vibration. Both incandescent (particularly those not rated for "rough duty") and CFLs work poorly in areas with fans (like an exhaust fan/light in a bathroom) or vibrations like garage doors.
That's not to say they don't have downsides. The cost can be quite high. Some energy companies subsidize them to encourage people to switch, but without subsidies, they can retail for $10-20 and up. The good news is hopefully you'll never need to replace them. They also don't work in all dimmers, particularly older ones, like those manufactured over 10 years ago.
Also, they tend to be sensitive to high heat. Some people have had issues with using flood lights in insulated canisters or in enclosures. Check if they're enclosure safe before using in such an application.
In most cases, if you can use a CFL, use a CFL. Particularly in more marginal applications (rooms that are not on often, like closets), your break-even point is going to be in the years, not months. Some people like the lights of an LED better, but there's clearly an additional cost to them. With some bulbs like A19s, the cost may not be that much more expensive to warrant the advantages (instant on, dimmable, better quality light), and obviously the more you use the lights, the quicker the payback will be. But if the benefits of an LED get you to use them instead of an incandescent, it's definitely worth checking out.
posted by Joe Carlin at 8:07 PM
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