Lumen output is the SI derived
unit of luminous flux, a measure of the total amount of visible light emitted
by a source. What does this means to picking
the proper LED bulbs or fixtures?
fixture or lamp has a lumen output rating.
Because LED fixtures and lamps have a directional light source they can produce
more light at a lower lumen output than incandescent or HID’s. This means there is less wasted and unusable
output is measured in photopic and scotopic lumens; however, it is the scotopic
lumens that enhance the visibility as seen by the human eye. LED’s produce light energy that is more
favorable to the scotopic response of the eye allowing a brighter appearance.
Lamp Comparison in Lumens:
Color temperature is a measurement
in degrees Kelvin that indicates the hue of a specific light source. Picking the right color temperature can be
the most important decision when buying a LED light source. LED’s come in many different Kelvin
temperatures and if you are not familiar with temperature ratings you can make
wrong decision when buying LED products.
products come in many various shades from bright white, which can almost look blue, to a soft white
like you would put in a table side lamp.
A good rule of thumb is to use soft white (2700-3000K) indoors and
bright white outdoors (3500-5000K).
These numbers are known as the Kelvin Temperature Rating, the higher the
number the brighter the shade of white light produced and the lower the
yellower or warmer the light produced.
Refer to this chart:
Lifetime of LEDs
The lifetime of LED light
sources can vary quite a bit, therefore you should observe this closely when picking
out an LED product. LEDs can range from
20,000 hours up to 60 and even 70,000 hours of lifetime. This could potentially mean that your LED
bulb or fixture could last up to 15+ years if burning a reasonable amount each
Example: Burning 8 hours a day is 2,920 hours a year, if
your LED product has a 50,000 hour lifetime that would be over 17 years.
the individual LED itself is what will shorten the life of the LED bulb or
fixture. The better the heat sink or
heat dissipation the longer the LED id going to last. Most LED bulbs can’t get the heat away from
the LED so most lamps have a shorter life span than a fixture that would have a
better heat sink and therefor have a longer life span. Most LED bulbs are not rated to go in an
enclosed fixture, be sure to check this because it can drastically reduce
lifetime of the LED.
Buying a Quality
There seems to be an unlimited supply of manufacturers producing LED bulbs in today's market. Some of these manufacturers can produce false information leading to you buying an inferior LED product. There are several thing you can do to protect yourself from this happening.
Buying from a reputable company
Buying from a reputable company is the key to a successful investment in LED lighting. We have found that some off brand LED manufacturers can sell an inferior product while telling you that it is not. This is truly where you will find the old saying "you get what you pay for" to be true.
Also, a lot of LED manufacturers may not be around in the near future like a major manufacturer like Philips Lighting. The inportance of this is that most LED manufacturers offer a 5 year or more warranty on their LED products, if by chance yo had a problem with your product the warranty is voided once they are out of business. Plus a lot of LED purchases will be bought in phases and not all at once, you should buy the same brand to keep the visual appeal consistent throught you home or business. If the manufacturer is out of business you will not keep this consistency.
Look for the lighting facts label
On your next LED lighting purchase, look for the lighting facts label and read it carefully. The United States Department of Energy wants to keep you informed about LED lighting you purchase and how it will perform. Lighting Manufacturers that display this label on their products agree to meet government regulated criteria in the following ares.
- Correlated Color Temperature (CCT)
- Color Rendering Index (CRI)
The chart below will explain the Lighting Facts Label
Do your research
There are things you can look for to help you make a successful purchase:
- Look for a reputable manufacturer
- Look at color temperature
- Look at Lumen output and lumens per watt
- Be sure they have a lighting facts label