The marketplace for more-or-less normal-looking LED light bulbs became just a little more crowded yesterday, when Philips announced the dimmable 75-watt equivalent version of its SlimStyle bulb. With an output of 1,100 lumens, it's a significant step up from the 60-watt equivalent 800-lumen model that previously sat at the top of the SlimStyle line.
There's a reason that we say "more-or-less normal-looking" ... while the SlimStyle looks like a regular light bulb when viewed face-on, it's flat when seen in profile. This design reportedly draws heat away from Luxeon LEDs inside, so no aluminum heat sink is required. That lack of a heat sink means that less work and material are required to build the bulb, plus it has a lower shipping weight – all of which are reflected in its relatively low price.
According to Philips, the new bulb consumes 13 watts of power, and should last for approximately 25,000 hours. Also, despite its asymmetrical design, it is claimed to produce even, omni-directional light.
It's available now for US$12.97, although instant in-store rebates in some markets will drive that price down to $7.97. The latter is the same price as Cree's new LED light bulb which also does away with the heat sink and looks more like a regular light bulb, although it tops out at a 60-watt equivalent 815-lumen model.
Source: Philips
I'm sure other sites have better information on the relative merits of each, but I bought the Philips first, because it had the coolest outer covering for the light emitting portion as sampled with a cheap Harbor Freight remote infrared thermometer (good enough for me to spot heater duct leaks, hot bearings, etc).
Then I bought a CREE that had a lower temperature outer covering of the light emitting portion (cooler to the hand than the Philips). I thought I made a better choice until my son-in-law asked how hot the heat sink was (temperature wise and electrically, since some seem to have become electrically hot). Mine wasn't electrically hot, but the temperature seemed about 1-1/2 times that of the hottest part of the Philips.
I may be overly concerned, but I prefer the coolest lights I can get since I had accidentally ended up throwing a late 50's synthetic sock off and having it land on top of a light bulb. We couldn't see it but we sure could smell it as we searched for the potential fire. I particularly avoid Halogen lights because of the temperature, the fires they have started, melting plastic grills on cars that have them carelessly installed, and the wiring damage done on older cars that weren't designed for the higher current bulbs.
Consider this amateur anecdotal food for thought, and research potential uses, or test your own applications accordingly.
I'm interested in eliminating the need for a converter/rectifier in every bulb, with attendant local heat generation, and, I would think less optimum cost per unit. I'd rather explore a more central (room at least) system that could put the heat generating portion in a more advantageous spot, and perhaps better control dimming of the entire room.
I bought 4 - for use in emergency exit signs at my office. I've given up completely on CFL's because they have nowhere near the life expectancy they claim. I put in the lowest wattage CFL I can find in these exit lights, and they last maybe 4 or 5 months before they burn out.
About 3 or 4 months ago, TSC stores were (again) putting Philips LED lights on some sort of fire sale, again with a rebate that took the price down to $5. These were pair-shaped (more "normal" looking) 60-watt equivalent Daylight spectrum LED bulbs that I think had a suggested retail price of $24. I bought 5 - they're really bright.
I don't know what it is, but either these lights are not selling well, or Philips really wants to corner the market and sell these things at a loss.
1: output in lumens --- the amount of light emitted
2. the number of watts consumed----- too many watts for fewer lumens means the bulb is wasting energy as HEAT... ( a VERY, VERY VERY expensive way to heat your home
3.the cost ... how much light do you get for the dollar... ( The bulb life is simply not important given the LONG life of leds..)
watch out for hype....
I am with aerojim regarding the desirability of a low voltage LED lighting circuit. Going by the minute number of amps drawn by these devices it would be a piece of cake to put a changeover relay in the line and feed the lights for the whole house from a battery when the mains supply drops out.
I have a handful of the 10.5 watt versions of this and there is some room to torque the bulb a bit extra if you need to adjust the angle some. I don't have any that are like 90 degrees from where I wanted them.
I have 8 - 40 watt LED bulbs in my ceiling fans and they work very well but the color temperature shifts towards the blue spectrum and makes everyone look a little sickly.