Introduction to LED Lighting

The Pros, Cons, and What You Should Know Before Buying LED Lights

LEDs are found in lots of objects we use every day—cell phones, televisions and monitors, holiday lights, traffic signals, flashlights, and are now commonly used in both residential and commercial lighting.  They are a much more efficient alternative to the traditional incandescent light bulb without the problems of the other alternative lighting options—compact fluorescent bulbs contain mercury and halogen bulbs emit UV radiation and have heat dissipation issues that can make them a fire danger when used improperly.

What are LEDs?

LED is short for Light Emitting Diode, and in the simplest terms, LED light is created by electricity passing through a semiconductor material through a process called electroluminescence (if you are dying to read more about electroluminescence, Wikipedia is a good place to start [https://en.wikipedia.org/wiki/Electroluminescence].

LED lights are not a bulb like we are used to thinking about them, even though they are often designed into a bulb shape to fit what the consumer is used to seeing and to fit into existing installations.  Instead of a having a filament like in a traditional incandescent bulb, LED light is emitted from an element, which is generally small and flat.  These elements can be placed really close together, creating very bright, concentrated light.

LED lights are commonly used for landscaping, in strip lighting (for under cabinet or stair tread lighting), in specifically-designed recessed cans, or as a replacement “bulb” for incandescent lights.

Benefits of LED Lighting

  • The biggest advantage of LED lighting is its efficiency—they use up to 90% less power and have a much longer lifespan than a standard incandescent bulb. So they save money over their lifetime both by decreasing power usage and the need to replace fewer bulbs.  Their efficiency is due to the fact that LEDs put out quite a bit less heat per watt than traditional incandescent bulbs, which can be useful in installations where heat is an issue, although LEDs still need to be built with a “heat sink” to keep the temperature from damaging the LED element.
  • LEDs can be used in colder temperature conditions than other bulbs—fluorescent bulbs are particularly troublesome in cold environments.
  • LEDs are a good choice in areas where the light is turned on and off a lot—unlike many other bulb types, the life expectancy of an LED is not diminished by cycling on and off.
  • LEDs do not need a “warm up time” and instead reach full brightness immediately.
  • An LED element is extremely flat, which makes it particularly good for applications where space is an issue, such as under cabinet lights, stair step lights or in niche spaces.

Eight Factors to consider when choosing an LED light

When deciding which LED bulb to purchase, look at the following qualities that manufacturers list for their LEDs.  Understanding what each means will help you get the correct look and feel of lighting as well as help you to avoid problems by choosing a light that doesn’t work in your situation.

  1. Color Rendering Index (CRI)—In simplest terms, CRI is a measure of how accurate the light from the LED element is when compared to natural lighting. This is measured on a scale going up to 100 where a higher score correlates to a more faithful representation of natural light.  Ever notice how certain colors look different under fluorescent lights than under incandescent lights?  That is because fluorescent lights have a lower CRI.  In general, look for a CRI of 80 or above for home applications.
  2. Kelvin Temperature—this represents the color of the light emitted from the LED. Light on the red end of the spectrum has a lower Kelvin temperature, while blue light has a higher Kelvin temperature.  If you are looking for warm, white light, a Kelvin Temperature in the range of 2,000k to 3,000K is best.   Cool, white light is in the range of 3,000K-4,500K, while daylight is in the range 4,500K to 6,500K.  Cell phones generally emit a Kelvin temperature upwards of 6,500K, which is considered very blue and studies have shown light in this range can affect your sleep when exposed close to bedtime.  Lighting color levels can be a very personal preference, but as a general rule:
    • Keep home living area lighting in the warm, white range. 2,700K is generally considered the sweet spot for living and dining areas, bedrooms, and general outdoor lighting, or in commercial spaces looking for ambient lighting–such as restaurants, hotels or spa lobbies.
    • Up the Kelvin temperature slightly, into the cool, white range (3,000K to 4,000K) for bathrooms, kitchens, and home offices, or commercially in retail spaces. This will give you a better “working” light that isn’t too bright.
    • Save higher Kelvin temperatures (4,000K +) for garages, work spaces, and in commercial applications such as grocery stores, hospitals, or warehouses.
  3. Lumen Count & Wattage—Lumen count is a measurement of the light’s output—how “bright” or “dim” it is. A lot of times, lumen count is confused with the Kelvin temperature, but Kelvin temperature measures the color of the light while lumen count measures the quantity of light emitted.  For those of us used to incandescent bulbs, we probably associate lumen count with watts—a 100W bulb emits more light than a 20W bulb; but watts actually measures the amount of energy consumed by a light.  LED lighting is vastly more efficient than incandescent lights, so a 100W incandescent bulb will have a much higher wattage (energy usage) than an LED bulb giving off the same amount of light (lumen count)—most manufacturers list “equivalent watts” to try and help consumers compare bulbs of different types.  As a general rule, use a higher lumen count for spaces that you want to be brighter.
  4. Dimmable—Not all LED elements can be dimmed, and not all dimmable LEDs will work (or work as expected) with every dimmer. LED elements that are incompatible with their paired dimmer will often flicker, not dim, or not dim as low as expected.  There is no easy answer here—LEDs are a constantly evolving technology that isn’t always in sync with the makers of dimmers.  Usually, LED manufacturers will list what dimmers it is compatible with and, conversely, dimmer manufacturers will publish a list of which bulbs work with their dimmers—doing a quick online search should net you that information.
  5. Enclosed Fixture Rating—The irony is that while LED lights produce much less heat than traditional incandescent bulbs, they are built using electronic drivers, which are heat sensitive. LEDs are built with a heat dissipater, which vary in how well they work.  Certain LEDs are specifically meant for enclosed spaces, and are listed as such.  Putting a non-rated fixture into an enclosed space is a quick way to burn out the element.  Recessed cans can fall into the non-enclosed rating, so read the spec sheet carefully when buying bulbs.  Be careful even with fixtures where the LED is contained in a small space—heat dissipation is a big issue.
  6. Life Hours—This is a measurement of how long an LED is expected to last. On the low end, LEDs are rated at 10,000 hours, while a lot of better-quality LEDs are rated to last upwards of 60,000 hours.   How often do you want to change your LED?  If you are installing an LED element in a high ceiling, it’s probably worth spending the extra money on an LED you won’t have to change again for 10 years.  If you are putting an LED into a floor lamp that is easy to change out, longevity may be a less important factor.
  7. Beam Angle—What direction do you want your light to go? Recessed cans focus light in one direction—down, while a floor lamp should send light out in all directions.  Use LED elements with a lower beam angle for situations where you are looking for accent or spot lighting and higher angles (often called omni-directional) for applications where you need light to spread out in all directions.
  8. Price—There are important differences between a $5 and a $40 LED. Higher quality LEDs are generally built with a better driver, have a higher CRI, have a better heat sink, have a longer warranty, are rated for more hours, and put out a higher ratio of light to heat (higher efficiency). Because of all these things, better quality LEDs cost more.  Prices have come down considerably in the past few years as LED lighting has become more popular and the technology has improved.  As a rule of thumb, if it is sold at a big box store at a low price, there’s a reason.  You can find much better quality LEDs at either a local electrical supplier or by ordering online.

There is no perfect LED for all applications, and there is often a tradeoff between the above factors.  LED elements with the highest efficiency often don’t have the best CRI.  Consider how much you want to spend versus how important the longevity of the LED is.  Make sure you purchase and LED rated for the application you are using it for—particularly in regard to dimming, enclosed spaces, and use in a damp location.

Disadvantages of LED Lighting

LED lighting is not a perfect solution in all situations, and it is important that you read the specs and compare that to how you intend to use the bulb.  Manufacturer warranties are very specific and do not cover using a bulb in a fixture it is not rated for.  Below are the biggest problems we’ve seen so far with LED lights:

  • The biggest issue that affects LED longevity is overheating the element–installing an LED bulb in an enclosed or small fixture that doesn’t allow for enough heat dissipation will cause the LED to fail much faster than the number of hours it is listed for. A flickering or on-off cycling LED may also be an indication of overheating.
  • Another disadvantage of LED lighting compared to standard incandescent lighting is initial cost—LED bulbs are quite a bit more expensive to purchase than standard incandescent bulbs. The cost savings of an LED element comes over time from both the energy savings and the much longer life compared to a traditional incandescent bulb.
  • The compatibility of LED elements and dimmers is still a problem, especially if you want to dim lights extremely low. A little bit of research before you buy your LEDs will save you some headaches on the back end.
  • As LEDs age, the amount and color of the light they emit degrades. They typically don’t fail in a sudden burst like incandescent bulbs (unless used improperly), but have a much longer, slower decline (this can be both a benefit & a disadvantage, depending on your point of view).

Recommendations

The most important recommendation is to match your bulb to your application—use the eight factors listed above to help choose the right LED for the right installation.  Avoid cheap bulbs–we’ve had good luck with both TCP and Soraa LED bulbs.  For recessed cans, we recommend installing a recessed can retrofit kit as a better option than just replacing an incandescent bulb with an LED.  LED strip lights are a great, less obtrusive alternative to fluorescent under cabinet lights.

 

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