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Issue #205 August 2007
Let's Count the Lumens
by Steve Ciarcia
The primary way most of us have been lowering power consumption is by swapping out incandescent lights with compact florescent lights (CFLs). Putting in a 15-W CFL in place of a 60-W incandescent amounts to a 75% average power saving—provided it works.
Like PV, I was one of the first people on the CFL bandwagon, too. About five years ago, the local power company offered CFLs at a real bargain and I bought over 100 lights. Don’t laugh, I have more lights around here than the average landing strip and they add up. (Heck, I’m sitting here on an 11' x 16' enclosed “porch” writing this editorial and I count 11 individual lights just out here.) Before we all got energy conscious and a kilowatt hour was $0.06 instead of $0.20, designing rooms with 20 to 30 track lights and banks of dimmer switches was the norm. The one saving grace in all of this incandescent lighting overkill is that much of my house uses “room occupancy sensing” via my home control system (HCS), and they are not just needlessly burning power all the time.
The unfortunate problem I ran into with CFLs was that you can’t just substitute them for every incandescent. It depends on the control circuit (manual switch versus something electronic). They absolutely didn’t like dimmer switches of any kind and they wouldn’t work properly with my HCS X-10 controllers either. Consequently, five years ago, I was able to swap out only about 20% of my incandescents with CFLs.
The encouraging responses from everyone cheering my PV installation along prompted me to take a new look at my lighting issues. I hoped that CFL ballast electronics had improved in five years. While I didn’t expect these new lights to all be dimmable, perhaps the new electronics might tolerate the full-on TRIAC of a dimmer switch and work with my X-10s. After buying another five dozen CFLs of various brands, I can categorically state that a game of roulette has better odds than making every kind of CFL automatically controlled. It’s too much to discuss here, but I’ll go into it more in my PV installation articles.
After not having much additional luck with newer CFLs, I then went “from the frying pan into the fire.” I decided to see if using LED lights would provide an alternative solution. After all, they offer the same energy reduction as CFLs if you read the advertising hype. Were they the best lighting solution since the whale oil lamp or just a new version with the same light level and no fishy smoke?
The first problem was separating the hype from the real facts when it came to the people selling LED bulbs. It’s easy to come away with the impression that LED lights, like CFLs, are an instant swap for incandescents. As an LED lighting neophyte, I eventually put my trust in Best Home LED Lighting (www.besthomeledlighting.com) and sampled or purchased a dozen different LED bulbs to experiment with. Again, I’ll cover this in greater detail in later articles, but let me give you the punchline while I have your attention. Basically, if the lumen level is acceptable, LED bulbs work well with simple AC line toggle switches, but anything else and it’s back to Vegas. Ironically, we all think of LEDs as being much simpler electronics than a CFL and hence easier to control. My reality was that I can’t even tell you that two units of the dozen LEDs I tried have the same electronic configuration. Hence, any automatic control devices are an adventure in customization. Here is the short list of my experience:
1. LED lights have a wide range of efficiencies and configurations. Current units seem to be about 50 lm/W, while new high-output bulbs are approaching 100 lm/W.
2. The number of LEDs is not the determining factor of bulb brightness. Different types of LEDs vary greatly in brightness. A better indicator of luminous intensity is the quoted bulb wattage. Current generation white LEDs are about 30 lm/W, while the newest power LEDs from CREE seem to be about 65 lm/W.
3. Currently, there are no LED bulbs that can match the light output of a regular 60-W incandescent bulb. The brightest LED bulbs are directional floodlights and spotlights with the brightest being comparable to a 45- to 50-W incandescent. The brightest nondirectional LED bulbs are more like a 25-W incandescent.
4. In my experience, LED bulbs don’t like dimmer controls because most 120-V AC dimmers need a minimum amount of resistive load in order to function properly. Because most of these bulbs are under 10 W and many have reactive-capacitive loads, TRIACs go nuts.
5. In my experience LED bulbs don’t like traditional X-10 modules either. While some LEDs may turn on successfully, many will not turn off. Instead, the trickle current used to sense manual lamp or appliance control causes the LED to flash.
6. No one wants to admit that the biggest problem with using LEDs is heat—they self-destruct. Currently, most manufacturers tell you not to install LED bulbs in enclosed ceiling fixtures for that reason. Ironically, the multi-LED bulbs have a larger surface area to dissipate heat even if they are less efficient. The new high-intensity CREE bulbs are more efficient, but they are constructed on a large aluminum heatsink for a reason.
Don’t get me wrong. Even with all my criticism, I think LED bulbs are the real future of lighting. In my opinion, right now they are at the same evolutionary point that CFLs were five to eight years ago. I’m encouraged that in just the few weeks I’ve been playing with them, I’ve seen a doubling in lighting efficiency and power. It won’t be long before there really is a 7-W 800-lm LED that doesn’t double as a space heater. I don’t mind being early on every bandwagon when I see progress like this. Stay tuned. The fun is just starting.
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