CENTRIC DAYLIGHT™ Full Spectrum Flicker-Free A21 15W LED Bulb

These color temperature options correspond to the various shades of natural light. 4000K is similar to the warmer and softer shade of morning sunshine. 5000K approximates the bright sun during mid-day, while 6500K is most similar to the crisp, blue color of the sky.

The choice between these colors is completely up to you! There is no correct answer, and this is a question of preference.

Regardless of your choice, all color options feature 95 CRI and flicker-free light output, which will provide you with all of the benefits of full-spectrum light.

Below are some articles that go into further detail:

Difference Between 5000K and 6500K

An In-Depth Look at 4000K

4 Things to Consider Before Buying 6500K Bulbs

Still not sure? Take advantage of our 30 day free-returns policy to try out the different colors. If you don't like it, simply let us know and we'll send over a return label.

The most popular color temperature option for home and residential use is either 2700K or 3000K, commonly labeled warm white. These are the color temperatures that match the warm and inviting glow of traditional incandescent bulbs. 

Keep in mind that the CENTRIC DAYLIGHT™ product does not feature warm white color temperatures, but daylight white colors, designed to match natural light, and not incandescent bulb colors. You will find them to be more of a true white color, providing you with light that is crisp and energizing. You may also find that they do not "mesh" well aesthetically with other warm white bulbs in your home.

If you're looking for a bulb that produces a softer, incandescent-like glow, we would recommend our CENTRIC HOME™ product line, which offers the same 95 CRI and flicker-free performance but with warm-white color temperatures.

These bulbs are a great fit for many applications that require a simulation of natural daylight.

For technical or visual arts applications that depend on visual assessment and a closer adherence to international standards such as D50 and D65, we recommend our NorthLux™ Series A19 LED lamps.

Yes, they do!

You may have read or heard about the concerns regarding the blue light hazard. Excessive blue light exposure during evening hours is certainly a concern, but blue light is an essential and important part of our daily lives, as it is extremely abundant in natural daylight (the blue sky!) and an important signal to our bodies and circadian rhythms.

CENTRIC DAYLIGHT™ bulbs are the industry's best approximation of natural daylight (95 CRI), and therefore contain similar relative levels of blue light in the spectrum as natural light.

You can think of these bulbs as mini suns that you can turn on and off at the flip of a switch. If you are concerned about blue light during evening hours and the potential impact on your sleep, we would not recommend using these bulbs at night when the actual sun has already set.

During the daytime, however, these bulbs are an excellent way to supplement or substitute for natural light.

We generally recommend using one bulb for every 20 square feet of space. Simply divide the square footage of your space by 20 to get the number of bulbs needed. For example, a 100 square foot area would require 100 divided by 20, or 5 bulbs.

While this may seem like a lot of brightness, do keep in mind that daylight color temperatures generally require a higher level of brightness for comfort due to a phenomenon described by the Kruithof curve.

For more guidance, we recommend checking out our lumen estimation calculator.

Unfortunately, these bulbs are not dimmable. This means that they cannot be used on any electrical circuit which has a dimmer installed, even if you keep the dimmer at the maximum setting at all times.

These bulbs do not emit any ultraviolet radiation. The light output covers the entire visible spectrum between 420 nanometers and 800 nanometers, but does not go below (UV-A) or above (infrared).

These A21 bulbs have a standard screw-in base (E26), which is the same type that has been used for more than a century.

As long as the lamp fixture is designated for an A type or A21 type, these bulbs will be compatible.

Although these lamps have the brightness of 100 watt incandescent lamps, these lamps have an actual power draw of only 15 watts. Therefore, they can safely be used in fixtures that have a max rating of less than 100 watts.

The voltage range of this product is AC 90-240V and 50-60 Hz, which covers all global voltages. As such, they can safely be used internationally without any issues. The internal circuitry adjusts for the input voltage automatically, and does not affect the light output or performance of the lamp.