How to choose LED bulbs


To make sure whether it is suitable for our LED lamp holder is our top priority when we select LED bulbs. The standard specification of the type E27 is correspondent with the traditional one. On the other hand, E17 is for the smaller lamp Base and E11 is the halogen lamp. E27, 17, 11 represents the diameter 27, 17, and 11mm respectively. The indication is normally on the box. If it is ambiguous, you can directly recognize it with the measurement.


LED is the new star in the lighting world. There are so many choices out there. Having trouble to choose a right LED bulb? How can you find a right one for yourself? Here are few tips to help you.

Lumens (You pay for LUMENS, not for WATTS) When we measure weight, we use pounds or kilograms. When it comes to light, we use lumens. Lumen is a measure of the total “amount” of visible light emitted by a source. A 100W incandescent bulb can emit 1600 lm of light. When you find a LED bulb marked 100W equivalent, it means That LED bulb can generate 1600 lm of light. One important question for that is how many watts that LED bulb consumed to generate 1600 lm of light. Of course, the less that LED bulb consumed, the more the energy saved. For example, there are two LED bulbs all marked 100W equivalent. One used 18W of energy and the other used 13W of energy. You can easily tell which one can save you more energy. The one consuming 13W of energy has better emitting efficiency. Its maker has better technologies to bring you 1600 lm from 13W of energy. So, when you choose a LED bulb, you pay for lumen and choose the one which consumes less energy for same lumen. The Table-A above shows the relationship of lumen and watt equivalent to an incandescent bulb.

How to choose LED bulbs

Beam Angle

Generally speaking, incandescent bulbs and compact fluorescent bulbs emitted light beams in around 300 degree, shown in Fig-1. We say that their beam angles are omni-directional. When it comes to LED, there are 2 types, directional and omni-directional. LED chip emits light beams in narrow angle, usually 120 degree, as shown in Fig-2. It is not much trouble to design directional LED bulbs. Most of manufactures want customers to feel familiar to buy and to fit into most of existing light fixtures. They made their directional LED bulbs look like incandescent light bulbs. But, it takes more works to design omni-directional LED bulbs due to the nature of LED narrow beam angle. Manufacturers must play some tricks to spread LED’s light beams to wider angle. That’s why you see LED light bulbs in so many different shapes on markets. Here are some examples shown in Fig-3.

Directional bulbs spread most of light beams in 120 degree as shown in Fig-4 and Omnidirectional bulbs spread in 260 degree as shown in Fig-5. So, if you compare a directional LED bulb of 1600 lm with an omnidirectional LED bulb, you can find that the directional LED bulb has much more light toward its front and the omnidirectional LED bulb has much more light toward its sides. Here comes a question. Where do you need directional or/and omni-directional LED bulbs to install in? If you spread same amount of light in a narrow angle area, you can get more light in that area. For example, you use a directional LED bulb of 1600 lm and an omni-directional LED bulb of 1600 lm on same ceiling. You can get much better brightness under the directional LED bulb than you can get under the omni-directional LED bulb. It is like you spread same amount of water on a smaller area and a wider area. So, when you install a LED bulb on ceilings, it is better to choose directional LED bulb. Directional LED bulbs have a disadvantage. Its beam angle is around 120 degree. When you install it in light fixtures like shown in Fig-6, you can find that the lampshade is dark. In this case, you need omni-directional LED bulbs as shown in Fig-6. So, now you know what differences are between directional and omnidirectional LED bulbs. Generally speaking, If you need side light from a LED bulb or to avoid a dark lampshade, for example, desk lamps, you choose omnidirectional bulbs. If you need a more efficient down light, you choose directional bulbs. Here are some hits showing in Fig-7 which may help.

Another general rules to make choices. Choose directional when the bulb is oriented face down or such that all light needs to be directed to a certain area. Choose omni-directional when you need light to go towards all directions to illuminate a fixture or space.

It is quite trouble, isn’t it? Is there any bulb for all purposes available on the markets? Yes, there is. XLEDIA designed special lens which we called diamond stars as shown in Fig-8. This special designed lens can reflect just enough light beams to keep lampshade bright and still lead most of its light toward its front. So, you can have strong light beams to illuminate your need and still have shining lampshade. One extra saving is that you do not need to buy all different types of LED bulbs for your various light fixtures at home and you can switch the LED bulbs from one fixture to the others.

Enclosed Fixture Suitable

It is well known that LED is very sensitive to heat. When temperature rises, the efficiency of LED drops, and its lifespan shortens. Most of lighting fixtures are enclosed fixtures. Here are some examples in Fig-1.The enclosed fixtures mean the air circulation or heat exchange are very limited. The heat generated by LED goes nowhere but contaminating itself. It causes the raising of LED temperature. So, it becomes an issue to extend the lifespan of LED in the environment like that. When you shop for LED bulbs, look for LEDs that are approved for enclosed fixtures.

ALL XLEDIA’s LED bulbs have been tested through UL1993 standard with temperature and passed. Our design can hold the LED bulbs in an enclosed fixture and maintain the long life time without overheated. When you use the LED bulb with the feature of “enclosed fixture suitable” in a non-enclosed fixture, the LED bulb can even perform better and extend its life time.

* The real life time of a LED bulb will be effected by the sizes of fixture and hours of usage.

IC Rated Fixture Suitable

IC rated fixture Suitable Since 1982, building codes mandate that recessed lights must be IC-rated to prevent fires. IC stands for Insulation Contact”. There are insulation materials on ceilings or attics to keep temperature in houses and to save energy. The recessed lights on ceiling are surrounded by the insulation. These fixtures of recessed lights are IC-rated. You need LED light bulbs of “Insulation Contact Suitable” for IC-rated recessed fixtures. The IC-rated fixture insulates the heat from dissipating into environment and to prevent heat leakage, ice dam and fire, and to save energy, but it also isolates the heat generated by LED and causes LED short lifetime and failure. When you shop for LED bulbs, look for LEDs that are approved for IC rated fixtures.

XLEDIA LED bulbs for IC rated fixtures have been tested through UL1598 recessed fixture standard with thermal insulation and passed. LED bulbs from XLEDIA (selected items) equip special designs and can be used in IC-rataed and/or enclosed fixture, and still keep long lifetime and great performance. These products are the first commercial available in North America

How do I know if my fixture is IC-rated or not?

1. You don’t have to climb into your attic and dig around in the insulation to see if you have IC rated lighting. In most cases, you can remove the light bulb, be sure to let it cool because these bulbs get hot. Then you can pull down the trim and a label should be on the inside. If you find IC rated label on the fixtures, you have to use LED light bulbs with “insulation contact suitable”. If you don’t see the label, it probably is non-IC rated.

2. Since 1982, building codes mandate that recessed lights must be IC-rated to prevent fires. if you have no idea whether your fixtures are IC rated or not, it is better to choose LED bulbs of “insulation contact suitable” for safety reason. For end users, if they use our LED bulbs of insulation contact suitable in a non-IC rated recessed light fixture, the lifetime of LED bulbs can be as good as in an IC-rated fixture. You won’t go wrong.

Color Temperature

What does the color temperature mean?

When you exam the lighting facts on the package of the LED bulb you purchased, you can see the item, color temperature. For most of consumers, color temperature means cool white or warm white. Actually, there are a lot of more. The color temperature of a light source is the temperature of an ideal black-body radiator that radiates light of comparable hue to that of the light source. Color temperature is a characteristic of visible light that has important applications in lighting, photography, videography, publishing, manufacturing, astrophysics, horticulture, and other fields. It is measured in kelvin. This is too technical and probably does not make much sense to people. The table A might make it more meaningful to general public.

2700k-Incandescent lamps

3000k-Warm White compact fluorescent lamps

4000k-Moon light

5000k-Day light at noon

6000k~7500k-LCD screen Cloudy day

Here is a simple test to see how color temperature distorts true color of a object. Choose 2 exact same light fixtures with white lampshades as shown in Fig-A. In Fig-A, a 2700k LED bulb was installed in the right fixture and a 3000k LED bulb was installed in the left fixture. Amazingly, the 2 exact white lampshades showed different colors. As shown in Fig-A, the lampshade illuminated by the 2700k LED bulb showed the same color as an incandescent bulb would do but the one by 3000k LED bulb showed pinkish color.

he Fig-B showed the result of the same method but with 5000k and 6500k LED bulbs. The lampshade, on the right, with the 5000k LED bulb showed its true white color but the one, on the left, with 6500k LED bulb showed greenish color. You can use your LED bulb to illuminate a piece of white paper to see if your LED bulb can show the paper’s true color. So, now you know how to choose color temperature.

XLEDIA carefully selects high quality LED chips to deliver superior quality of light. All XLEDIA cool white LED bulbs are 5000k and warm white are 2700k

Energy Saving

It has been well-known that LED bulb can save energy. An 100W incandescent bulb generates light of 1600 lm. A energy saving compact fluorescent light bulb needs about 26W to generate the same amount of light but LED needs about 12.2W(depending on the maker’s technology). The Table-A shows the efficiency of each type of bulbs. Obviously, the LED bulb’s efficiency is much better than the others’. A LED bulb can save more than 80% of enery compared to an incandescent bulb.

There is another question. All LED bulbs claim energy saving. Which one should I choose? There is a simple math to know which one can do better job. You can calculate the efficiency of a LED bulb. The efficiency is how many lumens a LED bulb can generate by consuming one watt. You can check the lighting facts on the package of a LED bulb. You find its lumens and watts. For example, 2000 lm and 16.3W.

Efficiency = 2000 lm/ 16.3W = 122.7 lm/W

The higher the number, the more energy you save. By calculating the efficiency, you can know which LED bulb can save you more energy.

XLEDIA’s LED bulbs meet the requirement of 2017 Japan TOP RUNNER, which is 110 lm/W for cool white and 98.6 lm/W for warm white. You can save our planet more by choosing LED bulbs with better efficiency.


Generally speaking, LED light bulbs are the replacement of incandescent and florescent bulbs and installed in their fixtures. The size of a LED bulb plays an important role to deliver comfort light. As you can see on the Fig-1 above, it is a same fixture but installed 3 different light bulbs to compare the degree of glare. The longer the bulb is, the worse the glare is. It is quite difficult to design a LED bulb with high lumen and small size, because that a LED bulb need certain volume to dissipate its heat. So, it becomes an Olympic game to push the envelope on reducing size and energy consumption of LED bulbs and increasing its lumen. XLEDIA developed several unique technologies to bring all of these together. XLEDIA were the first company launched 1520 lm with the exact size of an incandescent bulb (60x110mm or 2.4”x4.3”). It is the most compact size in this industry. Its compact size in the recessed fixture can significantly cut the light emitting into your eyes directly and reduce the glare.

Fig-2 is another sample that wrong sizes cause glare. Many fixtures were designed with the size of the original Edison bulb which was diameter 2.36”x length 4.33” (dia 60×110 mm). So, if you choose a replacement with larger sizes, the wrong size of LED bulbs may cause glare as shown in Fig-2.

Heat Dissipation

Heat dissipation is always a great challenge to the engineers who design LED bulbs. LED is very sensitive to heat. The more heat you can draw out of LED, the more light you get. XLEDIA developed several unique technologies to solve this problem. First, we chose the high efficient LEDs which could generate more light with same amount of energy. Second, we used high thermal conductive materials to conduct heat to heat sink with minimum loss. Third, we designed a special heat sink with TTR structure which could transfer heat to the air very effectively. Basically, we did everything we could to reduce the heat generated from LED, and to dissipated the heat through very effective thermal management. Please see the picture above. It shows that XLEDIA’s LED bulb is 10 degree C cooler than others under same energy consumption.



Understand the warranty. What is covered and what is not? Is the warranty period a reasonable fractionof the claimed lifetime? Will the manufacturer have compatible replacement parts as applicable, when needed?

XLEDIA Limited Warranty:
XLEDIA warrants that this bulb will be free from defects in materials and workmanship, and will operate for a period of 3 years under normal usage based on up to 24 hours usage per day/7days a week, when used in accordance with package and bulb directions. If this bulb does not match the warranty, XLEDIA will send you a replacement bulb, or, you can exchange it from the shop you purchased this bulb from upon receipt of the returned bulb, register receipt, and proof of purchase. Please contact local agents or write to XLEDIA at to find out how to return the bulb. XLEDIA is committed to make high quality products. Returning bulbs will help us to monitor and further improve product quality. This limited warranty does not cover products subject to accident, neglect, abuse, misuse, or acts of God. This replacement or refund is the sole remedy available, whether in contract, in tort or otherwise arising from the failure of bulb and is in lieu of all other warranties, express or implied, including any warranty of merchantability or fitness for a particular purpose liability for incidental or consequential damages is hereby expressly excluded.


Focus on qualifying suppliers. Understand what methods the vendor is using to support reliability or lifetime claims, and require data. As they become available, require compliance with industry-consensus robustness tests. In general, if LED bulbs can be certified by ETL or UL in North America, it means what all you should concern about safety have been taken good care of. The followings are the marks you may want to look for on packages of products. Many manufacturers don’t send their products to third-parties for safety tests and to be certified.

XLEDIA’s LED light bulbs have been independently tested and meet North America, European Economic Area, and Japan safety standards. Every day, more and more consumers recognize XLEDIA on products they purchase as a symbol of safety.

If you find this mark on package, this means that this product have been tested by ETL according to the North Amercia Safety standards except electromagnetic compatibility, EMC.

If you find this mark on package, this means that this product have been tested by UL according to the North Amercia Safety standards except electromagnetic compatibility, EMC.

FCC realized that it was necessary to impose limits on the electromagnetic emissions of these devices in order to minimize the potential that they would interfere with radio and wire communications. As a result the FCC set limits on the radiated and conducted emissions of digital devices. If you find this mark on package, this means that this product has have been tested according to FCC regulations. The law makes it illegal to market digital devices that have not had their conducted and radiated emissions measured and verified to be within the limits set for by the FCC regulations. This means that devices that have not been measured to pass the requirements can not be sold, marketed, shipped, or even be offered for sale. It happens that you can hear buzz sound from speakers near by LED bulbs which don’t pass FCC regulations. The radiated emissions from LED bulbs interfere the speakers and created the noise.

XLEDIA’s LED light bulbs have been independently tested and meet North America, European Economic Area, and Japan safety standards. Every day, more and more consumers recognize XLEDIA on products they purchase as a symbol of safety.

LED Bulbs For Home

Choose LED bulbs according to the height where you want to install them

Choose LED bulbs according to the height where you want to install them

First, you identify what lumen you need from a LED bulb for the location installed. For example, the bulb is placed on a desk or table. You might need 640 lm up. For the bulbs installed on ceiling or wall for illumination of hall way, isle or balcony, 1000 lm up is necessary. For living room or dining room, 1000 lm up is recommended.