Lamp definitions
10 Things to Consider When Purchasing LED Lighting
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
Although LEDs run cooler than incandescent lamps they still generate heat and need to be cooled. The more power used in a LED lamp the more heat is generated and this can adversely affect the long term lamp performance as excessive heat can perminently degrade the LED light output.
HT Lighting frequently upgrades its products to the latest LEDs technology from renowned manufacturers. Our electrical circuits never drive the LEDs to their maximum rated current. This means HT Lighting products generate less heat and are less likely to degrade in light performance, ensuring a longer economic life.
4: Colour temperature (Kelvins) and Rendering Index (CRI)
When white LED lighting ffrst became available it quickly gained a reputation for creating cold or blue colour tones. As technology has developed LED colour temperatures have advanced and today LED Luminaires are available in a wide range of colours temperatures, from similar to natural day light or the warm tungsten glow of traditional incandescent lamps.
LED colours set the tone and feel of your vessel so choosing Luminaires that complement your interior or exterior is important.
HT Lighting LED interior lamps are usually available in either 2700-3000K (warm white) or 5000K (day white) colour options
Think about what feel you want on your vessel. Cooler white colours (5000K) usually suit white gel-coat boats and exteriors, while lush upholstery or varnished timbers look and feel better with a warmer (3000K) light.
CRI ratings >80 produce natural colours
It is also worth explaining that affer LEDs have been manufactured they get selected into various grades based on their colour temperature and efffciency.
HT Lighting ensures they use the same brightness and colour temperature grade to ensure consistency of the luminaire, meaning a number of lamps fftted to a room will all have the same appearance e.g colour temperature and intensity.
5: Thermal Management
The notion that LED lamps run cool only when comparing to incandescent lamps that are too hot to safely touch affer operating for a short period. The fact is the LEDs and the electronics inside a lamp do heat up and if not cooled effectively will affect the light performance and the expected life span of the lamp. A very hot running LED Luminaire can also cause issues when interacting with the surrounding materials, particularly in recessed lamps, that prevents the heat to dissipate.
Competitors lamp HT Lighting LED 90
Thermal image of two different LED lamps and the heat each generates.
High power LED lamps do generate heat so the lamp needs to be designed to efffciently transport this heat away from the LED itself. LEDs that overheat, meaning the junction temperature of the LED rises above a set threshold, will permanently degrade, signiffcantly reducing their luminous efffcacy.
Well engineered thermal management of a LED device is essential for long-term reliability.
High output lamps should be designed to dissipate heat through heat sinks or thermally conductive materials. HT Lighting use aluminium housings with radiating cooling ffns to dissipate heat over large surface areas away from the lamp.
HT Lighting has also introduced a revolutionary new ceramic based thermal polymer that has unique heat distribution properties. This will be explained further when we discuss the importance of the materials used to manufacture durable and reliable LED lamps.
6: Materials
Maritime environments are very harsh, salty, high humidity and coupled with strong UV. Lamps manufactured using low grade, corrosive metals or poorly coated alloys soon degrade and rust. This can cause unsightly rust stains on the vessel and blemish the appearance of the lamp. Eventually the housing and sealing systems will break down allowing moisture to enter the lamp. Once this happens it’s only a matter of time until the electronics fail.
HT Lighting only manufactures products from materials which are highly resistant to UV radiation, salt and permanent high humidity.
Offering excellent transparency (similar to glass) and characterised by its very high impact and fatigue strength Grilamid® is also resistant to long term UV exposure and chemically induced stress cracking.
The replacement of metal based housing heat-sinks with thermally conductive plastic not only opens a myriad of design options.
7: Sealing (IP Rating)
As LEDs are electronic devices it is important to protect them from moisture and other contaminants that will degrade or harm the lamp. In a marine environment this is even more important as the chance of getting water, condensation or salt spray around the lamp is highly likely even in interior applications.
The most effective way to protect the lamp and its internal
components is by completely sealing the lamp.
All commercial and leisure HT Lighting LED lamps are at least IP 67 rated, meaning the same luminaire can be fftted to both the interior and exterior on your vessel, in either wet or dry conditions. With the same fully sealed LED light fftted both on the interior and exterior, a consistent lighting scheme can be kept and the vessel can be safely cleaned or water blasted without fear of water ingress into the lamps.
8: Electro Magnetic Interference (EMI)
Electromagnetic Compatibility (EMC) is an increasingly relevant safety concern, especially for many emergency and industrial applications. As electronic devices such as LED lamps become more common, so does the risk of unintended electromagnetic interference (EMI) that can have adverse effects on other sensitive devices such as radios or communication equipment.
All HT Lighting LED products are tested and certiffed to international standard CE for electromagnetic interference. HT Lighting recognises the importance of low emissions, so products are designed to have values signiffcantly below the recognised levels for international standards, and lower than market norms.
9: Warranty
We hope this illustrate has been helpful and explained the many factors that contribute to the design and manufacture of quality and reliable LED lamps. Depending on the brand of LED lamp purchased you can expect between a 12 month and 7 year warranty and this commitment of the manufacturer will be an indication for the conffdence level a manufacturer places in the long-term durability of his product.
Buy from a trusted brand with a reputation who will stand behind their products.
10: Cost
Obviously cost is an important consideration when making a purchase decision. Quality LED lamps are usually more expensive than incandescent lamps and there are price differences between LED lamps as well. As explained in this booklet there are vast differences as to the material choices and construction methods and standards a manufacturer designs to.
It is important to not only consider the initial expense but the replacement and life-time cost of the lamp or your vessel.
The power saving and longer life span usually well off-sets the initial price paid over the life-time of the LED lamp. How well a LED lamp is designed, engineered and made will determine the eventual life span. Consider the total cost of purchase, maintenance and efffciency, repair and replacement costs when purchasing your next LED product. Astute purchasers prefer to pay for a quality lamp with increased output, efffciency, light patterns and a 5 year warranty.
For more information on HT Lighting Limited’s extensive range of LED lighting solutions and the unique features and beneffts of each product ，please visit http://www.ht-lights.com