Evaluating Light Output: How many Watts is that LED?

When looking to define the output of a light source most people will look for its wattage. Traditional incandescent lighting has made it a rule that a 100 watt lamp will output more light than a 60 watt lamp. This is because all incandescent lamps use the same filament material which is heated to the same temperature, so the only way to increase the light output of these lamps is to increase the wattage. This is one of the main reasons why incandescent lighting wastes so much energy. 
However, LED light sources are much efficient at converting watts to lumens. Each material which can be used withing LED sources themselves has its own light extraction efficacy. For this and other reasons, two different LED sources can consume the same wattage but different lumen outputs.  Therefore watts can not be used as an index of light output in LED light sources. 
Evaluating the 'brightness' of LED sources for each situation requires you to think differently about lighting. A 60 watt incandescent lamp emits a total light output of roughly 800 lumens, but the light is equally emitted in all directions. When you're reading at your office desk, your book does not receive all the 800 lumens from your desktop lamp, nor should it need to. 
The most important measurement is delivered light. According to the IES ( Illuminating Engineering Society) serious reading requires 500 lux on the page. Many linear LED under-cabinet fixtures and task lights can deliver this level of light whilst consuming far less than 60 watts. 
So, wattage is no longer a relevant measurement to understanding the light output of a lamp, you might want to consider this when choosing which LED  lamp you require. 

Please visit www.theledspecialist.co.uk to see our full range of LED lighting. 




This blog post has been adapted from Philips' evaluating light output: technical brief. 

Philips present the world's first clear LED lamp

Global lighting innovators Philips, have bought the traditional incandescent lamp into the 21st century by combining the aesthetic beauty of incandescent lamps with the latest LED technology. Philips' clear LED lamp has a unique innovative lens which emits beautiful light whilst retaining the classic shape of incandescent lamps. 

This latest development is the biggest change to incandescent lighting in the past 100 years. This 40 watt lamp contains the first LED capable of emitting light in all directions. Whilst maintaining the elegant shape and sparkling light of traditional incandescent lamps, Philips' clear LED lamp saves energy, has a lifetime of 25,000 hours, emits 470 lumens and even when dimmed maintains the same brightness levels as its 40 watt incandescent counterpart. 

Philips noted consumers' reluctance to switch-over to LEDs within the home as home-owners want to hold onto the traditional warm light and shape of incandescent lamps. Philips' clear LED lamp allows customers to hold onto the light they love whilst enjoying all the benefits of modern LED technology. The clear LED means the classic shaped lamp keeps its original beauty making it a seamless replacement for the standard 40 watt (A60 shape) lamp. This lamp is ideal for application in the living room and other areas where quality of lighting really matters. 

Rene van Schooten, CEO Light Sources & Electronics for Philips Lighting said: “With our L-prize LED bulb we showed that we could match the quality of incandescent light. With our clear LED bulb we’ve combined the aesthetic beauty and shape of the traditional incandescent with the benefits of LED. Using our innovations in LED the bulb is highly energy efficient, saving up to £8 per lamp per year.”

                               Features of Philips’ clear LED bulb:

• Innovative lens for sparkling filament like light effect
• Dimmable
• Shape: A60
• Lifetime: 25,000 hours
• Colour Temp: 2700K
• Lumens: 470
• Energy efficient and cost saving: 85% energy efficiency (6w input wattage: 78 lumen per watt ratio)
• Perfect light distribution (omnidirectional): >240D
• Ideal for application in homes, hospitality and retail

Discover how much you could save with Philips' lighting solutions...