Q?What are the standard comparisons used to evaluate the colour quality of light sources?
  • Colour Rendering Index – CRI indicates the accuracy with which a light source such as an LED can reveal the various colours of an object. The standard CRI system is based on eight colours across the spectrum.
  • Additional R-values of CRI are used to represent certain colours. The appropriate R-values are application specific. For example R9 represents red and is good for lighting for lighting flesh. It also tends to make the light Warmer.
  • Colour Quality Scale CQS is a new system that uses a wider palette of 15 reference colours as against the smaller palette of 8 reference colours used for the CRI system.
Q?What defines the colour temperature of a white LED?

The thickness of the phosphor layer and the wavelength of the blue chip influence the colour temperature of the LED.

Q?What does correlated colour temperature, CCT, mean?

Colour temperature defines the colour appearance of a white LED. CCT is defined in degrees Kelvin where a Warm light is around 2700K moving to Neutral White at around 4000K to Cool white, 5000K or more. Note that CCT does not tell you anything about the colour rendering ability of the LED.

Q?What does LED stand for?

LED is short for light-emitting diode.

Q?How long do LEDs last?

LEDs are notable for being extremely long-lasting products. Many LEDs have a rated life of up to 100,000 hours. This is approximately 100 times longer than a typical incandescent, 400-50 times longer than a typical halogen, and 16-20 times longer than a typical CFL. Used 12 hours a day, a 100,000 bulb will last more than 22 years. Used 8 hours a day, it will last 34 years!

Q?Where can LEDs be used?

They can be used almost anywhere. LED replacements are available for all applications such as parking lot, canopy, signage, can lighting, recessed troffers, and much much more.

Q?What are the advantages of switching to LED?

The advantages of switching to LED are numerous. Here are just some of the benefits: LEDs use much less electricity than other bulbs, have extremely long rated lives, produce very little heat, do not emit UV or infrared, contain no mercury, are resistant to shock and vibration, and can operate effectively in extremely cold environments.

Q?What’s the quality of LED light?

If you buy quality product, the light quality is excellent. Color Rendering Index (CRI) is generally used to measure light quality on a scale from 1-100. Many of our LEDs have a CRI rating of at least 90.

Q?How green are LEDs?

LEDs are very green. For starters, they use much less electricity than many other lighting products. This means that less electricity has to be produced to operate them, and resulting in lower emissions from power plants, especially in areas where coal-fired plants are common. Unlike CFLs, they contain no mercury. Because of their long life, they also reduce solid waste: If you replace an incandescent bulb with an LED, you will prevent fifty 1,000 hour incandescent bulbs from being thrown away. Additionally, they produce very little heat and can reduce energy usage related to HVAC. The U.S. Department of Energy has estimated that increased adoption of LEDs over the next 15 years would also reduce electricity demands from lighting by 62 percent, prevent 258 million metric tons of carbon emissions, and eliminate the need for 133 new power plants.

Q?Are there rebates/incentives/tax credits available for switching to LED?

In many cases, yes. In order to find out if you are eligible for a rebate or other incentive program, please call a Grenentec Lighting Specialist.

Q?Why is the life of LEDs measured as lumen depreciation?

Unlike conventional light sources that reduce in output and eventually fail, LED products do not normally suddenly fail. Instead, the light output reduces over time.

The normal convention is to quote the life when the output has reduced by 30%. I.e. when there is 70% light output remaining. This is often quoted as the L70 life and is measured in hours.

Q?What are the factors that affect the lifespan of the LEDs?
  • The thermal management of the LEDs.  If LEDs come on a standalone chip, appropriate heat sinks have to be designed to prevent premature failure of LEDs.
  • The electrical stress: Running LEDs at currents higher than specified make the LED run hot. This can happen with wrongly matched drivers. E.g. the driver produces 700mA whereas the LED needs 350mA stresses the LEDs and reduces its lifespan.
  • Higher ambient temperatures than that for which the product is rated reduces the life of the LEDs.
Q?Why are LEDs considered more efficient than conventional light sources?

In many cases when comparing the lumen output between LEDs and conventional light sources, LEDs may have lower lumen value However LEDs are directional light sources. All the lumens emitted from an LED are directed towards the task area; while conventional sources emit light in all directions which are then modulated in a given direction with optical systems like reflectors and lenses. The proportion of lumens that falls in the task area from an LED light source is greater than that of a  conventional light source.

Q?How is light produced in an LED?

Light emitting diodes produce light by the movement of electrons between the two terminals of diode by a process called electroluminescence. When a light emitting diode is electrically connected, electrons start moving at the junction of the N-type and P-type semiconductors in the diode. When there is a jump over of electrons at the p-n junction, the electron loses a portion of its energy. In regular diodes this energy loss is in the form of heat. However, in LEDs the specific type of N and P conductors produce photons (light) instead of heat. The amount of energy lost defines the colour of light produced

Q?How are LEDs different from other light sources in the way they produce light?

LEDs produce light by direct conversion of electrical energy to light energy.

On the other hand, incandescent light sources produce light by heating a filament until it grows red hot. Linear and compact fluorescent lamps use a UV discharge plus a phosphor to produce the light. HID lamps use the ionisation of gases in a discharge tube which in turn produce photons.

Q?Do LEDs require time to reach maximum brightness?

No. LEDs directly convert electrical energy to photons. It is a one step process of electroluminescence that does not require time to reach maximum output. Other sources such as fluorescents or HID work on discharge technology. This requires an arc to warm up and may take a few minutes to reach full output.

Q?How is white light produced by LEDs?

LEDs do not directly produce white light. There are two ways in which white light is produced from LEDs as below:

Using a blue LED with a phosphor coating to convert blue light to white light by a process called fluorescence.

Combining red blue and green LEDs to produce white light. White light is produced by varying the intensities of the individual red, blue and green chips.

Q?How is coloured light produced from LEDs?

The colour of light produced is dependent on the inorganic material used in the P-type and N-type semiconductor. Different inorganic materials in the semiconductor release different amounts of energy when the LED is connected to a power supply. This amount of energy released defines the colour of light produced. For example, red is a low energy light and blue is a high energy light.

Q?Can the product be financed?

Yes, Through our Term Financing program the capital outlay can be
reduced to 36, 48 or 60 month terms that are also 100% depreciable up
to $250,000, then 50% per dollar based on IRS 2008 Economic Stimulus
Act 179 {consult your CPA}

Q?Does LED work with my existing parking lot poles?

Yes, you do not need to replace your parking lot poles. The
LED fixtures are designed to be mounted exactly like your
existing metal halide or HPS fixtures. There is no modification