Is this something you've ever experienced? While you are driving home from a shopping center or an apartment parking lot at night, you see the lights appear bluish or purple instead of white.As a property manager, business owner or facilities director, you might ask yourself:
- LED Parking Lot Lights Color Change?
- Is the purple or blue tint an indication of failing light?
- Do blue tinted lights emit more or less light and are they safer?
- Which colour temperature is most appropriate for property security?
Let's discuss the reasons behind the color changes of LED parking lights, what triggers these changes and what can be done to ensure they do not occur.
What Is Color Temperature in LED Lighting?
Another misunderstanding related to consumers would be "bluer" or "whiter" lights are better because they deliver more light (lumens). In fact, the appearance of light source is decided by a parameter called Correlated Color Temperature (CCT) in Kelvin (K) scale.
As stated by the United States Department of Energy (DOE) - LED Lighting Basics, "Color temperature refers to the color tone of a particular light source, and does not affect the amount of light produced (lumens), or the energy efficiency of the lamp."
Commercial outdoor lighting generally falls into these categories:
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3000K (Warm White): Gentle, warm white light generally utilized for home or outside restaurant seating.
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4000K (Neutral White): A pure white Neutral White light close to the natural term of moonlight. Provides great visibility without glare.
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5000K (Cool White): Tight, bright daylight tone standard for high security applications and commercial buildings.
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6500K (Daylight White): An intense, very blue version of white light that is commonly used for industrial lighting;
The take away is: A 5000k led parking lot light is not really "brighter" than a 4000k that is the same wattage; it just appears cooler and fresher to the human eye.
White Parking Lot Lights: The Standard Choice
Almost all contemporary commercial parking lots use either 4000K or 5000K LED fixtures. These are the Color temperature terms preferred by property managers for two significant reasons:
Superior Nighttime Visibility
White light offers the maximum contrast which allows the driver to see the pedestrians, road markings as well as navigate around obstacles.
Enhanced Security Camera Performance
Even a high definition surveillance system cannot correctly identify vehicle color, license plates and faces if the quality of light is not optimum.
That concludes yet another vital number in the world of lighting-Color Rendering Index (CRI).
CRI indicates whether a light source can display object colors realistically, as opposed to natural daylight. The Lighting facts used by the U.S. Department of Energy states that is it important when security and visual identification are critical.
For general outdoor parking lots, a CRI of 70 or higher is recommended so that a red car appears red, not gray, when viewed by security cameras.
Why Do Some Parking Lot Lights Look Blue?
A blue hue on a parking lot light generally can be attributed to one of two issues, either the art of concession, or early power supply component failure.
High Color Temperature Specifications
Some facilities actually put in 6000k or 6500k fixtures. When that many blue-photoreceptor (short wavelength) cells are stimulated, the output has a putrid bluish-white hue.
The International Commission on Light (CIE) has set specifications for world colorimetry describing the effect of spectral power distributions upon the way humans perceive color. Viewing high-CCT lighting produces high contrast but can contribute to excessive glare and sky glow when the fixture is not fully shielded.
Early-Stage Component Shift
Should a part that was once brilliant white start looking a little cool and blue, you can rest assured that this is typically a first warning sign of a hardware failure called phosphor degradation.
What Causes Purple LED Lights?
If your parking lot lights have gone from white to a deep indigo (blue-purple) hue, you are suffering from a common manufacturing defect and not a design flaw. An indigo or purple hue to parking lot lights can only mean one thing,....
Almost all "white" commercial LEDs are really blue LEDs in disguise. The general term white LED fixture has a blue Light Emitting Diode (LED) chip at it's kernel. This blue chip is coated with a yellow phosphor layer that converts the blue light into the broad spectrum of a white LED light.
If the phosphor layer wears, cracks or delaminates from the chip, the raw blue and near-ultraviolet light from the underlying chip will pass through. If the phosphor layer fails as reported in the technical analyses of LEDs Magazine of LED reliability.
Lutz‐Dukes blue When the blue becomes so bright that it blends with the amber, red shifted remnants of the other phosphor, our eye perceives a purple/ violet color.
Why Do LED Parking Lot Lights Change Color Over Time?
Despite their longevity, poor manufacturing can lead to early failure for LEDs, especially outdoors. The following are the two main reasons for color shifting:
Subpar Thermal Management
LEDs run considerably cooler than old HID or metal halide bulbs, but inside they are extremely heat sensitive. Outdoor parking lot lights are subjected to hot summer heatwaves and to all night long exposure to thick vapor. Over the seasons, the temperature variations will take their toll. If there is not a significant aluminum heat sink, the inside temperature is going to reach high levels and the phosphor coating will end up baking, cracking and flaking off from the LED chip.
Low-Quality Materials
Cheaper budget lighting manufacturers may lighten costs by using lesser quality epoxy resins, silicon binders or other cheap binding agents to secure the phosphor in place. Over time this cheap material can start to yellow or break down when subjected to prolonged exposure to UV as well as heat, eventually leading to a quick change in color after only a few years.
Comparing Light Profiles: White vs. Blue vs. Purple
| Light Color | Root Cause | Is It Recommended for Parking Lots? | Action Required |
| White (4000K - 5000K) | Normal, high-quality LED performance. | Yes (Industry Standard) | None. Optimal for safety and security. |
| Blue (6000K+) | High color temperature design or early phosphor wear. | Conditional (Check glare and local dark-sky ordinances) | Monitor for further color shifting or glare complaints. |
| Purple | Severe phosphor degradation / fixture failure. | No | Replace immediately. Light output and security visibility are compromised. |
What Color Temperature Should You Choose?
Choosing the correct color temperature when retrofitting the property or replacing a failed fixture is a matter of compromise between safety, outside attraction and territory requirements.
Recommended CCT Applications:
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Residential Parking & HOA Lots: 3000K - 4000K (Reduce light pollution and maintain a warm inviting environment).
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Multi-family / apartment parking: 4000 K (Ability to provide security while maintaining convenient for residents)
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Retail & Commercial Property Lots: 4000K - 5000K(Maximize visibility, prevent praniest activity and allowthe property to maintain a modern appearance)
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High Security Perimeters: 5000K (Maximize clarity and contrast for these pictures for a security officer).
In general, 4000K or 5000K LED parking lot lights will give you the optimal amount of light in order to enhance visibility without creating an unpleasant, bluish, unnatural coloration.
How to Choose a Reliable LED Parking Lot Light
Below are crucial commercial-grade specifications to consider instead of watching the wattage and lumen numbers, if you want to keep your commercial lighting illuminated and lively for years:
Robust Thermal Design
Use fixtures utilizing the heavy duty aluminum die-cast housing and special heat sinks designed to have good heat dissipation performance. The better heat dissipation the best dispersion for phosphor aging.
Industry Certifications
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UL Listed: Confirms compliance of the fixture with the tough safety standards in the U. S.
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DLC Premium (DesignLights Consortium): Confirms the fixture has successfully undergone extensive performance, efficiency, and color stability testing. A fixture that has been DLC-certified will be able to take advantage of substantial utility rebates.
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IP65 or IP66 Rating: Assures that we are totally dust, rain, and snow proofing the house.
Conclusion
Purple parking lot lights or bright blue going dark signifies a reduction in a fixtures performance which can compromise the safety of the property.
Always select the best quality components when purchasing new LED parking lot lights. A high quality LED parking lot light offers a good thermal design and established certifications. This will maintain your property bright, safe and ever lasting.
