A few weeks ago I set up my 12V solar power in the apartment where my wife and i will be living for the winter. It is small and portable, a 47 watt panel, a gel cell deep cycle battery, 6 amp charge controller, and a 12 V 11 Watt com. fluor. lamp, and old car stereo. It provides about 50% of our lighting, as we can both read by it at night, and we dont light up the whole house. However I figured it only saved 5$ or so vs. using the 120 V AC power. I am thinking of buying a larger 12 V bulb for another lamp. Also it is probably not up to code, but should not be a fire hazard as there are auto fuses installed. The nice thing is that I can move it wherever I go.
Actually in lumens per watt CF still edges out LED's, but the big advantage of LED's are they put the light where you want it where a CF will throw it in all directions.
That used to be true (with the older LED technologies). But I don't think it's true of the newest LED technologies (i.e. the LEDs that have only been out for a year or two).
If I'm correctly remembering the chart I found (on the internet) a while back, most CF are only around 50-60 lumens/watt. While this is still a lot better than incandescent bulbs, some of the latest LEDs (already on the market) are already doing over 90 lumens/watt (close to twice CF's efficiency), and the designers are still working hard to push the efficiency even higher. And that's on top of what you just said about LEDs focusing better (i.e. putting the light exactly where you need it).
OTOH: LEDs aren't yet "cost effective" as primary lighting, as it just costs too much to make a LED module that puts out anywhere near the lumens that most homeowners expect for lighting a room. i.e. it will be much cheaper (from the standpoint of buying the "bulbs") to use CF to light your house, then to use LEDs. And the slight edge that (the newest) LEDs have in power efficiency, is still not enough to overcome their much higher initial expense in most cases (sort of like the early days of CF's, when the CF "bulbs" weren't "cost effective" to use everywhere due to their high initial expense). But for smaller lighting needs (such as small "task lighting"), LEDs already are carving out a nitch for themselves (even around the home). And as the price of LEDs starts going down over time, their practicality as (home) lighting will inch up.
Ok, regular incandescent’s run about 8 lumens per watt, halogen run about 12-15 lumens per watt, cold cathode and LED's typically run about 25 lumens per watt, HID run about 30 lumens per watt, fluorescent’s run about 40 lumens per watt and finally low pressure sodium (orangish street lights) run about 120 lumens per watt.
There are variables in all of these, they recently released a 5 watt LED running about 50 lumens per watt and I also saw a prototype 100w die running about 45%, very nice I have a pretty good inside lead to some of the manufactures and haven't heard of any production LED's over 50 lumens per watt, yet...
One of the neat things about LED's is as the voltage is lowered (thus reducing overall power) to the LED the lumens per watt actually goes up, while halogen and incandescent lamps the lumens per watt drops WAY off. So running a halogen lamp at 50% of its rated wattage will get you about 10% of the light output and running an LED at 50% of its rated wattage will typically net you about 60% of rated light output.
A lumen is a measurement of the total light output.
The other thing about LED lighting is that it doesn't blink like a CF or hum or produce a wicked amount of EMR - some of my old CF bulbs radiate like a bastard. Plus you CAN dim a LED really easy and they run directly on DC vs an inverter for the CF.
That is really weird they have all the numbers I have know about for a couple of years doubled, hummmmm. Either way in that article they say CF are about 80 lumens per watt and the cree is about 70 lumens per watt. Don't get me wrong I really like LED's. I have them in way to many places around our house and in over 200 flashlights I own, but at this time for area lighting CF still seems to be the direction to go.