LED Lighting Illuminated

November 26th, 2010 by Cathy Rust Leave a reply »

LED lighting has some significant advantages over both incandescent and compact fluorescent. For one thing it uses significantly less electricity which saves you money and puts less strain on any electricity system. For another, it doesn’t contain mercury or other harmful elements that our current lighting systems have. LED bulbs are fully recyclable and parts can be reused in new LED lights, and finally, if you buy the right bulbs, you won’t have to change them for years and years. But (there’s always a “but”) it’s also expensive and if you don’t choose the right bulbs you might not be satisfied with the results. LED isn’t like incandescent or compact fluorescent (CFL) lighting; if you want to be satisfied with your LED lighting, you’re best to hire a lighting consultant to guide you through your first (and possibly last) light bulb purchase.  I have been researching LED lighting for a few years now. Each time I visit IIDEX I take a half hour and go and talk to the lighting experts about LEDs for use as everyday lighting. I always ask the lighting reps: “Is it ready for prime time?” The answer, it turns out, depends on who you talk to. When I spoke with representatives from Phillips and GE the answer was “not yet, but it’s coming.” When I spoke with Dmitri Shaffer from evoLED Green Lighting Solutions, he said, “Of course it is, but it’s not as easy as walking into Home Depot and buying a replacement bulb.”

You’re telling me. When I first went on to evoLED’s website I was overwhelmed with the selection. I really didn’t know what my needs were, and considering the cost outlay for one bulb (averaging $40), the investment, if done properly, can be significant, and depending on how often your lights are on, so can the savings. So, the best solution was to book Dmitri for an appointment and have him come and take a look at my lighting needs. While he was here, I took the opportunity to ask a lot of questions the different LEDs available and how to choose one. It turns out that the reason you don’t want to buy one from the big box stores has more to do with familiarizing yourself with LEDs rather than the actual light bulb itself — although that too is an issue.

LED 50 watt halogen replacement bulb (9 watt version)

The quality of Light Emitting Diode “bulbs” is highly dependent upon the chip that is inside the light itself. The quality of this chip in turn will determine the longevity of the light. So, as Dmitri points out, “if an LED is selling for $10, don’t expect it to last the usual 40,000 to 100,000 hours expectant of a name brand LED.”  There are, in Dmitri’s opinion, three chip manufacturers that are the best, although he acknowledges that there are many manufacturers who are improving their chip quality all the time. The three chip manufacturers he recommends are CREE, Nichia, and Epistar. So how do you know whose chip is inside the LED you’re about to purchase? Ask your lighting professional. In theory, they should know who manufactures the chip inside the LED. I must say though, I have my doubts that sales people at the big box stores will be able to answer this question, but I’m happy to be proven wrong!

Another factor in an LED light’s longevity is the design of the light itself. According to Dmitri, each diode can use up to three watts of power. However, the more diodes the bulb has, the more likely the entire bulb will get hot, so another important factor in a light’s design is the size and quality of the heat sink. The larger the heat sink, the better, because it allows higher brightness without overheating the diodes. However, the manufacturers are confined to existing bulb sizes when trying to design a heat sink, so in small sizes, like the MR16 for example, they have to find the balance between brightness and heat management. Bright diodes without an adequate heat sink will fail shortly after the installation. Luckily, most manufactures take this into account.

Finally the design of the LED lamp is another important factor and consists of the size of the bulb, the number of diodes, the colour temperature of the light and the angle or span of the light.

Colour temperature. This term actually refers to the colour the light casts, not the heat emitted from the bulb, and is measured in degrees Kelvin. The cooler the light temperature, the whiter or crisper the light. If you’re interested in keeping the same cast as an incandescent bulb then the recommended light temperature is 2700K. As the Kelvin degree increases, the light becomes whiter then blue, as in daylight blue. I tested 3000K LEDs and the colour temperature provided both a crisper, white light, but without the cool colour that the daylight bulbs cast, which are usually between 4000 and 6000 K.

Another issue with LED lighting is the angle of the light. A 30 degree bulb casts a spotlight, whereas an 80 degree light casts a wider angle and the light disperses earlier, so ceiling height becomes an issue: if ceiling heights are 12 feet, probably a narrower angle is better because the light will likely still make it to eye level and maintain its intensity.

LED lights come in a variety of designs. Some are made for replacing your 50 watt halogen potlights, some are excellent for undermount lighting. Choosing one will depend on your fixture, where it is, and what the purpose of the light is (ie., task lighting or general lighting.

The light spectrum of an LED is much wider than a fluorescent, without the same heat emission as well. One thing to consider is depending on how often your lights are on, they may contribute to the heating of your home/business. Changing to LED lights will lessen the air conditioning load in the summer, but may increase the heating load in the winter.

I asked Dmitri what the main reasons were for people wanting to switch to LED lighting and it turns out there are two:  the first is to save money and energy, the second is comfort level. Undermount halogen lights turn out not to be great lights. They are hot, so food and wine shouldn’t be left underneath them, and they can leave unlit areas on the counter if the light pucks aren’t placed close enough together. Fluorescent undermount don’t contain the full light spectrum so decorative items can lack their usual colour. LED undermounts are in strips with the diodes placed so closely together that very little of the counter isn’t lit.

Regarding strength, or lumens, of light. One of the complaints of LED lighting is that the light output isn’t as strong as incandescent or CFL lighting. However, there has been a lot of progress in this area, and there are now sufficient substitutes to replace 50 watt halogen bulbs. When Dmitri did our lighting audit he told me to focus only on the the most used rooms in the house, which in our case is the kitchen. I estimate that on average, the kitchen lights are on for 5 hours per day, every day. There are 7 halogen and two 60 watt incandescent bulbs. We estimated that if we replaced all those bulbs, we would break even at the current electricity rate in 3 years and 9 months, which is much less time than I thought .

Having spoken with Dmitri, I now have a much better understanding of the complexities of LED lighting. I also believe that if you’re going to make an investment in LED lighting you’re best to call in a consultant who can help you choose the right bulbs based on your needs and your current lighting design.

Contact Dmitri Shaffer at evoLED for more information on having a lighting audit done in the Greater Toronto Area.

Advertisement

Leave a Reply

Get Adobe Flash player