The difference between LED Globes and what you may currently use.

Like if this Guide is helpful
Light globes are generally taken for granted in the home or in business but they are a large part of your home energy consumption and with a little thought, can be a factor in creating the mood and environment of the room .  Compared to purchasing the latest smart phone or home theatre system, how much time do we spend in selecting our light fittings, deciding how they are to set the mood in each room and how much energy they are consuming?

To highlight my point do you know
  • what type of light globe you currently use (incandescent, halogen, fluorescent, compact fluorescent, LED, HID)
  • how much power they are using (Watts) and
  • what is the amount of light they are outputting (Lumen)?

Today we have a greater choice and can have more control over our environment than ever before.  Follow me as I explain some facts about lighting and hopefully it will help you make good choices so when your guests walk into your home they go WOW!.

When we walk into a retail store we judge the feel and mood of the store in the first 3 seconds.  Usually this is dependent on the lighting used and how clean it is presented.  Lighting consultants are engaged to advise how best to use light to create the right shopping experience and create the right mood for shoppers.  Property Mangers monitor energy usage and together decisions are made to maximise the customer experience.  Light is one of the most important items in creating a comfortable environment and unfortunately we often neglect this in our homes.  Now you can be in control of this in your home.
 

Types of Light Globe

With the discovery of electricity many inventors in the mid 1800's were trying to develop a practical lighting solution for the home. An Englishman Sir Joseph Swann and American Thomas Edison both developed a solution around the same time in 1878 and 1879 respectively and from here we have never looked back. They used the theory that light is emitted from atoms in the form of energy when their electrons are excited. From this theory, all the different types of light globes/bulbs were developed but we are most familiar with the incandescent light.
 
Incandescent: A long, incredibly thin tungsten wire filament is supported by stiff wires and suspended in the middle of an oxygen free glass bulb which is filled with an inert gas.  An inert gas has very little reaction when introduced to other substances, and allows for maximum efficiency and prolonged life of the filament.  The length of the filament determines the light output and it's brightness.  If the filament was exposed to oxygen it would disintegrate.  An electric current is applied, exciting the filament and causing light to be emitted in the form of photons.  The light emitted is in both the visual and invisible spectrum.  Most of the light is in the invisible form, emitted in the infrared light spectrum and sometimes referred to as light noise.  The infrared light is a by-product of light creation in incandescent globes that cases fading of textiles and is wasted energy because we cannot see it or use it.

Incandescent lights are cheap and convenient but they get very hot, only about 15% of the electrical energy is converted to visible light and they do not last long (typically about a thousand hours). An incandescent light bulb is rated in Watts and usually the higher the power, the more light emitted.

   Advantages - inexpensive, convenient
   Disadvantages - inefficient, operate at high temperatures, only 15% of electrical energy is converted into visible light, short life, high infrared pollution.

Halogen: The Halogen lamp is very similar to the incandescent lamp with some design changes.  The tungsten filament is encased inside a small quartz envelope filled with a gas from the halogen group (fluorine or chlorine) whose very nature is to combine with tungsten vapour at high temperatures.  The tungsten vapours react with the halogen gas as they evaporate and are deposited back onto the tungsten filament thus prolonging the life of the filament.  As the quartz envelope is in the centre of the bulb, it is now possible to increase the temperature of the filament thus increasing the light output. 

   Advantages - inexpensive but more expensive than incandescent, convenient, brighter, longer life
   Disadvantages - inefficient, operate at very high temperatures, very bright cold white light, may explode if touched by moisture or grease


Fluorescent: These lamps were developed to increase light efficiency and reduce energy waste compared to the incandescent light globe technology.   They are found everywhere in offices, warehouses, retail outlets, workshops and homes.  A sealed glass tube containing a small amount of mercury, an inert gas, a phosphor powder coating on the inside of the glass and sealed together under very low pressure.  At each end of the tube are an electrode wired to an electric circuit supplied by an AC supply voltage.  When power is applied electrons flow from the electrode in one end to another electrode in the other end, migrating through the gas.  The energy changes some of the mercury from a liquid to a gas causing the electrons to collide with the mercury gas atoms, exciting the atoms and resulting in the release of light.  Most of the light emitted is in the ultraviolet range which is not visible to the eye.  When this ultraviolet light hits the phosphor powder, a visible white light is given off and the colour of the light can be varied by using different combinations of phosphors.
Fluorescent bulbs were developed to improve the colour of the light and for a improved use of energy.  Approximately 25% of the electrical energy is used to create light which is an improvement on the incandescent globe. The Compact Fluorescent (CFL) was developed to replace the incandescent light globe for the home and came with a E27 or B22 end cap fitting.

   Advantages - bright, operate at cool temperatures, improved colour choice, more energy efficient than incandescent
   Disadvantages - poor in cold environments, flicker, require ballast driver

Light Emitting Diode LED: The LED's are electronic components or semiconductors, usually made from silicon and are different from traditional light sources.  An LED lamp or luminaire consists of four critical components. 
  • An LED Array - consisting of several semiconductors mounted to a printed circuit board to emit light.
  • a Driver - an electronic device that provides the correct current and voltage to the LED's for  proper operation.
  • Optics - may be a lens, diffuser, reflector or a combination, and
  • Thermal management - conducts heat away from the LED using a heat sink, cooling vents, a small fan or other design mechanisms
The semiconductor consists of two layers of complex materials, one positive and the other negative that allow electrons to flow in one direction only.  When current is applied, electrons flow and energy is released.  Some of this is emitted as visible light and some is trapped as heat.  The challenge for designers is to remove the heat from the device or it will drastically reduce the life of the LED and control the light efficiently.  This is where the good manufacturers stand out above the rest with their design.

Depending on the composition, LED's can create light in different colours.  To create white light a blue LED is covered in with phosphor material which converts some of the light to other colours and the combination of all these colours produces white light.  The more phosphor used on the LED, the less blue light is in the mix and the warmer the white light.  Since phosphor conversion consumes energy, warm coloured LED's (with a higher phosphor coating) may produce  fewer lumens (lower light output) with some manufacturers.  A good designer can get around these issues to produce a bulb equivalent in function to the traditional bulbs with greatly improved efficiency.

   Advantages - energy efficient, long life, zero mercury, very low heat emission, zero light pollution, zero infrared, zero ultraviolet, operates efficiently in cold environments, high intensity light, good colour, electronically controllable.
   Disadvantages - design challenge for manufacturers, don't appreciate high temperatures over 40degC.

High intensity Discharge (HID) : These bulbs come in different types and are usually used in industrial applications.  The high pressure sodium (HPS) are typically used in street lighting, metal halide (MH) for outdoor car park lighting, low pressure sodium (LPS) used in industrial areas and street lighting; all operate at high temperatures and have delayed start up times.  These lamps are more efficient than incandescent lamps and work as the electric current excites the internal gasses to fluorescence, causing the emission of light.

   Advantages - very bright, operate outdoors, more energy efficient than incandescent
   Disadvantages - delayed start, large fittings not suitable for residential installations
 

What Colours are available

The wavelength of the light emitted by the process of electron excitement, determines the colour of the white light projected from the globe and is measured in degrees Kelvin.  This light is classified from Warm White to Cool White.  As displayed in the diagram, warm white has more yellow or warm tint and the cool white has more blue or cool tint.   Generally the warm colours are used for lighting in the home. 
For example:
  • an overcast sky is between 6500-7500K
  • sunlight at midday is about 5500K
  • natural daylight is 5000K
When we design light globes the colour range is
  • 2000K - candle
  • 2700K - incandescent light
  • 3000K - halogen light
  • 2700K to 6500K - LED, CFL and Fluorescent
By placing colour filters in front of the light, we can produce colours from the combination of Red, Blue and Green.
 

How is Power Measured

Power is related to energy and measured by multiplying together the voltage (V) applied to the fitting and the current (A) required to light it up.  Therefore a 100W globe in Australia would require 420mA to produce light.  [100W = 240V x 0.420A]  Typically the wattage of a globe would directly relate to the light output of the globe.  With energy saving globes and clever technology, the power has not a lot to do with light output and instead we measure it in Lumens.  You can see the LED equivalent globe, uses much less current to produce light. 

Your electricity supplier will charge you for the amount of power you consume per hour and is measured in Kilowatt Hours (kWh).  So if we use less current, we will be invoiced less for electricity.  Power companies charge up to 32 cents per kWh.  The table below shows typical power comparisons between incandescent and LED globes.
 
Incandescent Power (Watts) Voltage (Volts) Current (Amperes)   LED Power (Watts) Current (Amperes)
25W 240V 104mA   5W 21mA
40W 240V 167mA   8W 33mA
60W 240V 250mA   10W 42mA
75W 240V 313mA   13W 54mA
100W 240V 417mA      
 

How is light output measured - Efficacy

Efficacy in lighting design refers to the amount of light produced by a light source as a ration of the amount of power consumed to produce it and measured in Lumens/Watt.  A lumen is a measurement of the total amount of visible light and therefore the higher the value, the brighter the light.

An industry standard LM-79-08 was developed by the Illuminating Engineering Society of North America (IES) and has been adopted as the standard for measuring light output and colour.  The standard recommends Luminas Flux (output in Lumens), Intensity (Candela) and Colour (Colour temperature and CRI) be measured from the complete device and not based on the individual LED chips alone.  Philips is one company that already test to this standard.
 
LED Power Incandescent Power Efficacy
5W 25W 450L
8W 40W 608L
10W 60W 805L
13W 75W 1055L

How is globe lifetime measured

Life ratings are more detailed because they use predictions based on life testing typically shorter than the life of the LED product.  Standards LM-80-08 (standard for light output over time) and TM-21-11 (life measurement technique) recommend how life measurements should be extrapolated and how the tests should be conducted.  The larger manufacturers are already testing to these standards and hence their results can be compared.  Others who do not, cannot compare results and they may not be accurate.  Again Philips test all their globes against this standard.
 

Light Globe Comparison

This table compares high quality LED lamps to incandescent and compact fluorescent lamps.  These are general evaluations and not specific comparisons.

  LED Incandescent Fluorescent
Efficiency @ @ @ @ @ @ @ @ @ @ @
Life @ @ @ @ @ @ @ @ @ @ @ @ @
Colour @ @ @ @ @ @ @ @ @ @ @ @ @
Beam Control @ @ @ @ @ @ @ @ @ @ @
Dimming @ @ @ @ @ @ @ @ @ @ @ @
Instant on @ @ @ @ @ @ @
Environment @ @ @ @ @ @ @ @ @ @ @ @ @
Initial Cost @ @ @ @ @ @ @


















The future of lamp packaging

There will soon be compulsory requirements under the Energy Related Products Directive (ERP) for manufacturers to test their product to the IEC and PAS standards and then the information to be displayed on lamp packaging such as:
  •  ECO label rating energy efficiency from A++ to G
  • Functionality
  • Life expectancy
  • Lumen depreciation
  • Energy Efficiency (Lumens/Watt)
Have something to share, create your own Guide... Write a Guide
Explore more Guides