GeekPi

LED! LED! LED!

When it comes to lighting technology, that’s what I hear on an almost daily basis. The thing is though, most of these writers know next to nothing about lighting, and are taking all of their facts from a press release; which of course always puts the product in a positive light (pun intended).

The call for the LED is a noble, but misdirected mantra of the industry and public at large – at least with today’s technology. It’s a fairly well known fact that in most applications, regular Edison style incandescent (aka, ‘regular’ light bulbs) are a pretty big energy waster. Then came the big old fluorescent tubes that most offices have. And then came the compact fluorescent light (CFL), which twisted the bulb and make the light controlling ballast all in one unit. And one of the more recent technologies that shows promise is the Light Emitting Diode (LED). The thing is though, don’t get caught up in the hype and marketing! LED’s are not that efficient.

The Way To Compare Light Bulbs

Comparing a bulb’s wattage alone doesn’t make much sense, as you have to compare the bulb’s electrical consumption to the amount of light it puts out (lumens). Luckily, most brands list both of these numbers on their websites and product packaging, which will allow an informed consumer to make up their own mind about the most efficient bulb for their home or work. This measurement is called ‘lumens-per-watt,’ which is how you should compare the modern light bulb.

Weak Reporting Doesn’t Help

Here’s one of the latest cases I’ve seen of this misplaced LED love from ‘journalists.’

Engadget

“While you’re replacing your household incandescent light-bulbs with LEDs in a bid to save energy and possibly cash (over the 40,000-hour lifespan) you might want to consider these remote-controlled lamps from Sharp.”

Treehugger

“They don’t give us lumens for the L60AV model, but the DL-L601N LED Lamp delivers a brightness of 560 lumens, which is pretty high (Sharp claims it is “among the brightest in the industry”). The L60AV is probably not quite as efficient… Life for all the new Sharp LED lamps (including the tunable one) is 40,000 hours.”

The bloggers use some pretty wishy-washy terms in those descriptions, such as “save energy and possibly cash” along with “is probably not quite as efficient.” These are not complicated numbers to find out, and I’ll walk you through the same process. You are free to come to your own conclusions, but I believe you’ll find the same result as I do. LEDs, in most applications, are not worthwhile.

Applications where I like LED include: Small tight spaces where regular bulbs don’t fit, color changing needs, a not very bright spotlight, or in high vibration, extreme temperature areas. They don’t make for very good or efficient area lights, since their light spread are typically very narrow.

It’s All In The Numbers

Lets use the above case, and give a breakdown of just how efficient and useful these bulbs will be. Had any of the blogs actually read the details of the press release they directly linked to, they’d find these numbers too.

Let’s take a look at the specs of the top end LED bulb from Sharp:

Over to the right are the specs they list. Now I’ll give them a little wiggle room from my criticism, since this bulb has some pretty cool tech behind the color temperature changing, but it’s priced steeply at nearly $90. We can see the number of lumens of this bulb ranges from 450 to 300, depending on the color setting of the bulb. Regardless of output, it consumes 8.2 watts. Now I don’t scoff at that low wattage, considering most people still use 60 or 100 watt bulbs, but the LED’s low wattage isn’t much to be too proud about. Why? It’s all about how much light those few watts output.

So looking at those numbers, we can accurately deduce that the efficiency of this bulb is between 54.9 & 36.6 lumens-per-watt. Not too bad really. A typical Edison incandescent bulb does about 10 watts per lumen. So it’s easy to say in a press release: “Our LED bulbs are up to 5 times more efficient than a typical light bulb!” Which then gets repeated by most tech and green blogs.

The problem is that they’re not comparing the bulb to a typical CFL. If you head down to your local hardware store, you’ll likely come across something like this Sylvania CFL package. Each bulb uses 23 watts of power (3 times as much as the LED), but also outputs 1,400 lumens of light (which is 3.1 to 4.6 times the light). That works out to be a LED busting 61 lumens-per-watt. The real kicker though is that the CFL costs $4 each, versus the $80 of the LED bulb.

So when you look at it that way, for 95% cheaper, you can get a bulb that is not only more efficient with each watt, but also 3-5 times brighter than a dim LED bulb.

But Wait! THE MERCURY!!!

Yes, fluorescents, even the little ones, have mercury in them. Mercury does some really bad stuff when it gets inside of people, especially kids, so it’s quite important to keep it from seeping into groundwater. Bulb makers have been doing a good job of reducing mercury content in bulbs. Most new bulbs have less mercury than the size of the period at the end of this sentence. <— yep that period

Make sure you recycle them, or else you could get into some trouble: the EPA just cracked down on CBS broadcasting and Macy’s Inc. for their massive improper disposal of fluorescent bulbs. If you take a look around, there’s very likely a CFL recycling program at one of the stores you shop at. I know nearly every Lowes, Home Depot, Ikea, and Ace Hardware offer CFL recycling – along with most lighting and lamp stores. If you don’t go any of those places frequently, drop by one of my favorite sites Earth911.com – you can quickly find a local place to recycle just about anything. Using that site, I found 50 separate locations I can drop off CFL’s within 25 miles of my house, 5 of them within 5 miles.

What I do to make my household recycling easy is to take a simple plastic bin and collect my burned out bulbs. Once the little bin is full, which happens every couple of years, I take it down to the local dropoff. It’s not that hard.

Of course, if you get really serious into lighting and efficiency, I have yet to find anything that comes close to the 105+ lumens-per-watt my T-5 office lights use. When you do the math, that simple fluorescent bulb is 2 times as efficient as the best LED on the market.

*** Before any of you chime in with a reply about amazing 100+ lumen-per-watt LED lights in laboratories, as a consumer, unless I can buy it today, I don’t consider it to exist. I’ve seen way too many promising claims from labs that can never make it to market because they’re unable to be mass produced. If you can find me a more efficient LED bulb or lamp to bust my claims, that I can buy today, I’d love to hear about it ***

As a bonus, in the gallery below, you’ll see the size differences between the old T-12, the typical use T-8 and the small, dare I say it, sexy, T-5 fluorescent bulb.

Share on Facebook