General purpose LED bulbs seem to vary a LOT in price… from $1 per bulb to $40+ per bulb… and there doesn’t seem to be any tangible difference between them. I mean, some say they last longer, but it’s never enough to justify 10-20x the price. And the lumens per watt are pretty much the same. Am I missing something?
Lighting – How to choose which LED bulbs to put in the home
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Due to the lack of adequate answers, I decided to research the differences myself and provide an answer to the benefit of the community.
PAR Type Lamps
From a build quality and light control standpoint, PAR type lamps are generally considered superior. The explicit parabolic nature of the reflector means light is more precisely reflected directly out of the bulb cavity, with less dispersion, than an R or BR type lens. PAR type lamps, thanks to the design of the lens in front of the actual light emitting element (which is usually a given with home lighting...PAR in general can referr to a very wide variety of lighting which may or may not have a front lens, including high powered stage lighting). The lens is often fresnel in nature, are often additionally capable of focusing the more accurately reflected light into a brighter, narrower spot. The fact that they have a more precisely crafted lens means they are capable of being designed to emit beams of varying angular degrees wide (anywhere from 12° to 70°), with high intensity narrow beams or more diffuse wider beams, makes them highly flexible.
PAR type lamps are also frequently designed in such a way that makes them viable for outdoor use. Not all PAR type lamps are properly sealed for use in humid climates or areas where rain or other water could intrude upon the bulb, but many PAR type lamps are. This is a key difference between PAR and R or BR type lamps.
In terms of nomenclature, PAR lamps are usually designated with a number. The number of a PAR lamp, such as PAR38, gives the diameter of the lamp in inches. In the case of a PAR38, the diameter would be 4.75" (4 3/4"), or "thirty eight eighths of an inch." Common PAR lamp sizes for home are PAR20, PAR30, PAR38, with the latter being most common.
R Type Lamps
One of the more common types of flood light lamps for use indoors, the R-type lamp is a more cheaply constructed "reflector" type lamp. They are not particularly efficient in any key respect, their design is roughly defined and there are no strict rules or guidelines regarding the reflector. As such, R-type lamps generally produce a highly diffuse light with a broad angle.
They use a similar nomenclature as PAR type bulbs. For example, an R40 is a bulb 40/8ths of an inch in diameter, or 5". The two most common R-type lamp sizes are R40 and R30.
BR Type Lamps
Preceding the CFL and LED age of high efficiency lighting, the BR-type lamp was an attempt to produce a more efficient indoor-use only replacement for R-type lamps. Standing for "bulbous reflector", the design of a BR-type lamp is more strict. The reflector is designed in such a way as to more efficiently reflect light. They still produce fairly soft, diffuse light, however it is reflected in a narrower beam, thus more efficiently utilizing light produced by the internal emitter (filament, LED, or CFL spiral.)
They too use the same eighth-inch nomenclature as PAR and R type lamps. The most common sizes are BR40 and BR30.
CFL and LED R, BR, and PAR type lamps
While the core design of these types of lamps was implemented in the days of tungsten-filament (incandescent and halogen) bulbs, the design is still used for CFL and LED lamps. In the case of CFLs, the actual reflector efficiency is likely suspect (at least in the case of a PAR type lamp), as the design of a PAR lamp, and thus it's efficiency in utilizing light, is dependent on the size and location of the internal emitters. CFL spirals are usually used in CFL-based flood lamps, and CFL spirals are a very different kind of emitter than a filament or LED. LED based flood lamps probably resemble classic filament based flood lamps better than CFLs do.
LED and CFL Light Quality
In some experimentation of my own, LED-based PAR type lamps definitely seem to direct a far greater quantity of their light downward, where as CFL spiral-based lamps still generally produce a more diffused output. Depending on the type of lens in front of the emitter, the quality and shape of the projected light for both CFL and LED PAR type lamps can vary greatly, from caustic refraction to fairly diffuse. CFL R/BR type lamps nicely simulate their incandescent predecessors. LED R/BR type lamps do not seem to diffuse quite as well as CFLs, so if you are looking for diffuse flood lighting, CFL generally has a more pleasing diffusion.
LED PAR lamps definitely produce a greater amount of directed illumination, so if you need to brightly light anything, LED is probably the best choice. LED flood lamps are also usually fully dimmable, "instant" on (sometimes "instant" really means up to a half-second delay before light is actually emitted), and produce far greater consistency of color (CFL color consistency is often rather poor, and during cooler or cold days, CFL floods will frequently brighten, dim to a deep magenta, then slowly normalize as they warm). LED lamps, of all designs, are usually fully dimmable these days as well. Dimmable LED flood lamps are usually dimmable down to 10% illumination, with some from the better manufacturers (such as Lighting Science) often dimmable down to 5%. Dimming quality, smoothness, minimum output and consistency is vastly superior on LED compared to CFL, with no flicker, popping, blinking, or inconsistent dropout as is frequent with dimmable CFL lamps.
In terms of the quality of projected light, BR-type CFL lamps definitely produce a smoothly diffuse light with little visible pattern directly underneath each bulb. PAR type lamps, either CFL or LED, but more so in the case of LED, produce visible refraction patterns under each bulb. I believe this has a lot to do with the design of the lens, and when multiple flood lamps are used along a hall or in a kitchen, diffusion improves. LED PAR type lamps can be very bright, which is nice when you need light.
My Choice and Recommendation
I have chosen to refurnish my kitchen, and eventually my hallways, with Lighting Science 5000k and 3000k (or possibly 4000k) Dimmable PAR38 LED lamps. These puppies are about $34 each, however they have twice the lifetime rating of comparable lamps from all other manufacturers (50,000 hours @ 6hrs per day vs. 25,000 hours @3-6hrs per day). The light is not as diffuse as your standard R-type incandescent, but the color quality is far superior for those who have never much liked the deep orange color of a classic incandescent (the 3000k versions are closer to a halogen in color, and the 5000k produce a nice, clean, crisp neutral white.)
For the highest quality, I recommend the following. Since LED lamps are dimmable, it is recommended to use a dimming switch wherever you use high lumen LED PAR lamps (i.e. 800 lumen or brighter). Personally I use Lutron HED-certified digital dimmers with dimming setting memory. One push of the button and the lights fade up over about a 1.5 seconds to your pre-set brightness level. Another push of the button, and the lights fade to minimum brightness then off over several seconds. With 800 lumen bulbs, setting a Lutron digital dimmer one or two notches down from maximum brightness produces very pleasing illumination, with the added bonus that if you need more light, or wish to add light during the daytime to fully illuminate areas that might generally be in shadow, you have the ability to crank up the illumination beyond that pleasing level.
One reason bulbs can burn out quickly is if the voltage applied to them is higher than the expected voltage (120V in The USA). Wiring problems and bad transformers can cause the voltage to be out of spec. Another reason is if there is a loose connection somewhere, and the light flickers (causing unnecessary heating/cooling cycles). A third reason is if the light is in a confined space, and overheats.
In order to check the line voltage, you will need to use a voltmeter. The Kill-A-Watt is a very safe product to use to check the line voltage. Note that you should try a few different outlets, since there are generally two different phases of power (not really phases, but opposite polarities, 180 degrees apart) going into a typical house, and you need to check both of them.
Identifying a bad connection is trickier. Generally, you would see flickering lights, but to be sure you would want to use an oscilloscope or spectrum analyzer (expensive equipment). Sometimes a bad switch will cause a short flicker when the light is turned on. Replacing the light switches with new high quality switches could help.
Finally, have you noticed that the bulbs go out more quickly in certain places? Are those places more confined, causing the bulbs to heat up more? If so, you need to use lower wattage lights (such as CFL, halogen, or less bright incandescents) so that the bulb is less hot.
LED lights, halogens, and CFLs are all more efficient than incandescent lights. For the same amount of light output, they use less electricity, and generate less waste heat (keeping them cooler). In order to check if they meet your needs, compare the light output (in lumens) to that of the bulbs you are currently using. Don't go by the "equivalent" rating (such as 60W equivalent).... The amount of heat generated is nearly proportional to the wattage of the bulb (generally between 10 and 25 W). Another thing to look at is the color temperature, as measured in Kelvins. More orange lights will be around 2700 K, while more blue (daylight) bulbs will be around 5000 K.
PS: Advertised bulb lifetimes are usually assuming use of perhaps four hours per day. So, a seven year bulb may only last a bit over a year if it is left turned on continuously.
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Best Answer
You're missing a lot, but you might not care. You indicated longevity is not a factor, so that takes care of one category of differences. Let's note a few other common differences between cheap and expensive LED bulbs, so that you might make an informed choice based on what's important to you:
Improvements in Expensive LEDs compared to Cheap LEDs
Efficiency: usually good bulbs are more efficient, in terms of lumens/watt. With a dramatic difference (say 55 vs 85), the saved electricity can pay for the differences in the bulb, depending on power cost and duty cycle of the product's lifetime, which as noted, also tends to be longer on higher-quality bulbs.
Heat: dirt-cheap bulbs use cheaper internal power supplies that tend to generate waste heat. Better bulbs use a fancy electrical driver known as a "switch mode power supply", which can be up to 90% efficient, compared to a resistive or capacitive dropper with as low as 50% efficiency. Heat lowers lifetime, so if your bulb will be in a globe, can, or other enclosed area, this is a factor worth considering.
Color Quality: Better bulbs tend to have both higher CRI, and less color variation within models. I've gotten two dollar-tree bulbs from the same peg, and one was about 250deg cooler than the other. I've gotten two different phillips bulbs months apart and they both have identical coloring. If you don't have a lot of bulbs going at once, this is more important than when a bad apple can hide in the bunch. There's also some health/wellness concerns about an over-concentration of blue light, and it's bio-rhythm effects, and in this regard, the more-balanced light of quality bulbs would reason to have less impact.
Light Quality: Cheaper LEDs (especially those with cheap capacitive dropper internal power supplies) tend to flicker at mains. This can be more noticeable at night, and in your peripheral vision. Prolonged exposure causes some people headaches or just distracting corner-of-the-eye rainbows or flashes. If all your bulbs are the same and they all flicker, the effect can be quite pronounced and annoying.
Performance: cheap bulbs can take longer to turn on, which is especially noticeable when one switch controls many lights. This can make a good automation system seems laggy, which nobody wants. Another performance factor is backwards compatibility with existing dimmers, dusk-to-dawn sensors, motion detectors, etc. The parasitic current of such devices often causes less sophisticated bulbs to dimly flicker when the switch is off. Better bulbs use a couple of electronics-based tricks to eliminate or reduce such an effect (sensitive gate SCRs, bleeder resistors across caps, post-DC switching, etc). Also, some cheaper drivers can create audible noise, either a hum or whistle (especially when dimmed), but I've not heard that on quality bulbs. Lastly on this point, quality bulbs last longer, so if the bulb is hard to reach, like an outdoor yard light, that could be a strong consideration.
Considering all that, you still need to consider your usage as well. Weight the factors important you you (if any) and shop armed with the knowledge to get the best deal for your needs. You don't always needs the best, and I use dirt-cheap ones in some places myself, even after noting all the above!
You can likely live with a cheaper bulb you use 2 mins a day in a closet better than you can cheap task lighting. If you don't have enclosed lamps, heat's not a big factor. If you lived happily for years with mixed CFL+tungsten lights you probably won't care about color temp differences or CRI. If you don't pay a lot for grid power, efficiency isn't as important as it is for those off-grid. If you don't have dimmers or other "fancy" switches, backwards compat doesn't matter, etc.
You be the judge. You can spend $5k or $500k and get a reliable car. Same with stereos, or anything really. How much you need depends, but now you know what to look out for...