Wednesday, 8 January 2014

Energy-Efficient LED Lighting

There was a time when lighting your home was cheap and simple. Not any more! Incandescent light bulbs are cheap and produce a good quality of light, but they use a great deal of energy, up to 90% of which is wasted as heat. There have been efforts to develop a more efficient incandescent, but the improvements have been minimal. (Effective January 1, 2014, manufacturers can no longer supply the Canadian market with incandescent bulbs.)

For many years, CFLs (Compact Fluorescent Lights) were promoted as the solution. They were more energy efficient, and they could last a very long time. But it is not quite that simple. A CFL that is used continuously may last up to twice the rated lifetime, but a CFL that is only used for 15 minutes at a time, may last just 40% of its rated lifetime. In addition, like all fluorescent lights, each bulb contains a small amount of mercury, so it can be dangerous if broken and disposal is difficult.

Enter a new player on the scene – LED lighting. LED lighting has been around for a while (e.g. indicator lights on televisions, digital clocks, traffic lights), but until recently household use has been restricted due to cost and the difficulty of obtaining a good quality of light. That is changing as LED bulbs become cheaper and better.

How It Works 
The basic LED (Light Emitting Diode) is a semi conductor; electricity passes through the material in a single direction and it emits light. LED lighting is extremely energy efficient. Incandescent bulbs have 5% efficiency, CFLs have 20%, but LED bulbs can achieve 60% efficiency and the industry is aiming for 90%. In addition, LED bulbs can last for up to 20 years (depending on usage).

LEDs don’t run off the same current that is provided to buildings, so they require a power converter. And LEDs work best when they are cool, so the bulbs include a heat sink to disperse the small amounts of heat produced by the LED. Producing a bright light (greater than the equivalent of a 60-watt incandescent bulb) has been difficult, but the technology is improving rapidly.

The light from incandescent bulbs appears natural and attractive to the human eye. However, LEDs produce blue light, which can appear cold and less attractive. It can be transformed into white light by passing through phosphors. In some cases, if the phosphors are on the outside of the bulb, the bulb will appear yellow, but it will produce white light.

Purchasing LED Bulbs 
When purchasing a LED bulb, don’t be driven by price alone. You should also consider the bulb’s longevity and the quality of the light it will produce. Margery Conner, Designing with LEDs, says:

“Some de facto standards have emerged for LED bulbs: The light output should be equivalent to a 60W incandescent bulb – both in amount of light produced (at least 800 lumens) and in area covered (it should emit light in all directions, not just cast a spotlight on one area); the light quality should be a warm white (2700K-3000K); it should be able to work in an enclosure such as a track light or fan light fixture without shortening its life; it should be dimmable (meaning no flickering, even at the lowest settings); it should preferably be silent (less common than you might think); it should have at least a 5-year guarantee (but the longer the better); and it should cost less than $15. (That last one is a groundbreaking new thing–last year’s best bulb that met that criteria cost over $25.)” 

Conner is currently recommending the Cree Warm White, which is available in Canada (Home Depot is selling them for $16).

Non-Bulb Lighting 
LED bulbs are important because we can use them in our current fixtures. But LED can be used in other forms and fixtures. The LEAF lamp, designed by Yves Behar, is sculpture as well as light source. Virtual sky panels can mimic natural lighting in offices, while LED light strips can be cut to the length required. Even more unexpected uses for LED lighting can be found here and here.

Businesses and municipalities can expect to see substantial savings by switching over to LED lighting fixtures in street lights, car parks, warehouses, and other large facilities. Over the coming year, 149 car parks in the UK will be retrofitted with LED lights.

LED in Saskatchewan 
Municipalities are beginning to install LED street lights. The light is directed downward, so it also reduces light pollution. Dark sky (LED) lighting can be found along Innovation Boulevard in Saskatoon and in most parts of Regina’s Innovation Place.

Brian Sawatzky has been trying out LED lights at Confederation Inn in Saskatoon for a number of years and says that they’re particularly helpful in hard-to-reach areas and in places where the lights are left on 24 hours a day.

SaskPower provides a Commercial Lighting Incentive to non-residential customers who install premium energy-efficient lighting equipment, such as LED fixtures.

Further Information 
LED Lighting: A Primer to Lighting the Future by Sal Cangeloso provides an excellent explanation of how LED lighting works, what to consider when buying LED lights, and advice on when to throw out your CFLs.

2 comments:

  1. Thanks for the article.

    As far as I'm concerned, CFLs were, at best, a step sideways in the evolution of the bulb. The only way the energy savings adds up is if they lasted close to their rated life, on average. Unfortunately, I'm way below average on the life of my numerous CFLs. That means that I've actually consumed MORE energy by installing them than I would have if I had just stuck with incandescent. Instead of the energy being consumed in my home, it's consumed in China during their manufacture, and in the shipping, never mind the extra heavy metals involved.

    I am really hoping that LED lighting is the big leap forward that we were hoping for with CFLs, and I am optimistic.

    To me the best option in most cases: shut the lights off when not using them! Simple. Now, if only I could convince my wife & kids.

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