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10 Things to Consider When Purchasing LED Lighting
Views:75   Time:2024-1-23
Everyone knows the beneffts of LED lighting compared to traditional incandescent bulb based lighting. It is well published that LED Luminaires are some 90% more efffcient and also offer up to 25 times longer life span. So the decision to change from incandescent to LED technology is an easy one. However comparing LED based lighting to halogen lamps is like comparing apples and oranges.

Everyone knows the beneffts of LED lighting compared to traditional incandescent bulb based lighting. It is well published that LED Luminaires are some 90% more efffcient and also offer up to 25 times longer life span. So the decision to change from incandescent to LED technology is an easy one. However comparing LED based lighting to halogen lamps is like comparing apples and oranges.

With so many LED products on the market how do you decide which ones to purchase?

If you are looking at upgrading or building new with LED lighting there is usually a substantial cost involved, so you want to make sure you are selecting the best lamps for the purpose, meaning they will do the desired job well. It is also important that they provide the best value and return on

investment. This means they should last as long as promised and provide the light performance desired.

So to summarise it is important to compare apples with apples as they say.

Here are the 10 most important things to consider when deciding to invest in LED lighting.


1: Light Output

Unlike traditional incandescent lamps or halogen lamps where the amount of power a lamp uses (wattage) is usually a pretty fair indication for how bright it will be.

LED technology and LED light output has increased dramatically over the last few years. As a result there are large differences between LED Luminaires in light performance for the power consumed (lumens per watt).

Lumens are a common measurement used to describe the amount of light a lamp produces.

Example of suggested lumen comparisons

This measurement is too offen based on the LED’s manufactured rating (Raw Lumens) therfore it can be misleading and not the actual measure of useful light emitted by a LED lamp.

Factors such as the power used to drive the lamp, thermal losses and optic and lens losses as light rays travel through the lens all contribute to a possible 20-50% decrease of the light lumens emitted by the LED. Good optic skills, circuit design and material selection are required to minimise internal lumen losses.

Another more accurate measurement of actual light output is lux.

The best measure of a lamps true light output is by comparing lux diagrams.

Quality lighting manufacturers, using state of the art photometric equipment, are able to provide accurate lux or candela charts so consumers get a fair representation of the expected Luminaire performance.
Lux and candela ratings refer to the actual light intensity from the lamp at given distances and direction. This way you know what light levels to expect when designing your lighting layout.

 

Lux and Candela charts are more useful measurements when comparing LED lamp output

HT Lighting Limited use lux and candela diagrams to illustrate accurate light output and beam angles.

Other aspects to consider when reviewing luminaire performance include beam angle, and evenness of illumination, as well as colour temperature and colour rendering which we cover in later sections.


2: Beam Angle

If you stare directly into a LED luminaire, chances are it will appear bright and dazzle you. In fact looking directly at some of the high power LED chips for extended periods can be hazardous to the eye.

Example of a spread lens design

HT LIMITED LED lamps use efffcient lens and optic designs to reduce glare and eye strain while still projecting the light in an evenly distributed pattern.

For example down lights will offen have a wide spread optic to ffll a room and by overlapping the wide spread beams from several Luminaires shadows are reduced.

Alternatively other lamps like spotlights or courtesy lighting may be designed to focus or direct the light in a speciffc direction to achieve a speciffc effect.

Example of a narrower spot lens design

Make sure you select a luminaire with a lens that reduces eye strain and an optical design to suit your application.


3: Power Consumption

As mentioned earlier, LED lamps can save up to 90% of power compared to traditional incandescent lamps.

It is a common misconception that all 4W LED lamps produce the same light performance. A well designed 3 watt LED lamp could produce more light than a 4 watt lamp. Much of the performance greatly depends on the LED used and as mentioned earlier the quality of the optic, thermal management and electronic.

Do not judge an LED on Wattage alone, as two different 4 watt lamps may not have the same light output.

As LED technology is steadily advancing manufacturers have been able to produce LEDs with a much greater lumen per watt performance. This means lamps are getting brighter and your power consumption from lighting is reducing. So efffcacy, which is the measurement of lumens per watt, is an important consideration.

Graph illustrates how mass produced LEDs have become more efffcient over the last decade.

Note: measurements are raw (theoretical) lumens per watt.

Comparing lumens per watt.

If possible try and compare the lumens per watt to get an accurate measurement of what percentage of power is being used to effectively generate light. The more lumens per watt the more efffcient the lamp is, meaning less power is being used to generate the equivalent amount of light.

Example A Example B                                              HT Lighting LED90