- They last (essentially) forever, with MTBFs in the tens of thousands of hours (50,000 is common--more than five and a half years of constant operation).
- They use less energy than CFL bulbs, and substantially less energy than incandescents.
- They do not contain hazardous mercury.
- They are not affected by cold temperatures.
I have installed and tested a number of different LEDs over the last few months, and I have some recommendations.
First, and most important: Do not buy any LED lamp labelled "accent" or "decorative" and expect to get any useful light. These are nothing more than Christmas lights or indicator lights, are generally poorly made, and what light they do produce is usually a harsh bluish tone.
For a general purpose, non-dimmed light fixture, I recommend three of the EarthLEDs line, depending on how much light is required.
The EarthLED ThetaLux 9-Watt Warm White LED Light Bulb is about equivalent to a 75-watt incandescent; while its smaller cousin, the EarthLED ZetaLux 2 Pro 7-Watt Warm White LED Light Bulb is about equivalent to a 60-watt incandescent. For applications where less light is desired, the EarthLED ZetaLux 2 - Standard 6 Watt LED Light Bulb - Warm White (2700K) is also available, equivalent to a 40-watt incandescent. All three of these bulbs emit a warm white light, at 2700 Kelvin. Cool white bulbs are available as well.
A couple important notes on the EarthLED bulbs; they are substantially heavier than an incandescent, and somewhat heavier than a CFL, so be sure their intended fixture is sturdy enough. They cannot be used on a dimming circuit--they will function, but only when the circuit is all the way open. They are a directional light, radiating about 190 degrees centered on the top. This makes them ideal for downlights, but they are not suited for most floor lamps where the bulb points up. They are idea for torchiere style lamps, because of this. Finally, the manufacturer recommends that they not be installed in fully enclosed fixtures.
If the directional limitation of the EarthLED bulbs is a problem, or if a dimmable bulb is required, I recommend the Philips 409904 Dimmable AmbientLED 12.5-Watt A19 Light Bulb. This bulb, while it looks bizarre, is an excellent performer. They are equivalent in brightness to a 75-watt equivalent, and despite the yellow cover, it emits a very warm white light, also 2700K, and is fully dimmable. These bulbs are ideal for fixtures where the bulb is not readily visible, and can be used in enclosed fixtures.
LEDs can be ideal for outdoor fixtures as well. For PAR38 lamps (most motion sensor lights are this size), the EarthLEDs PAR38 is ideal. Despite it's high cost ($39.99 at this writing), it replaces a 75-watt incandescent with only nine watts, and, unlike a CFL floodlight, illuminates instantly even at -40F!
I have replaced nearly every light in our house with LEDs. While this is not necessarily a profitable investment, it has reduced our electric consumption substantially, down nearly 65% from one year ago. While LEDs aren't a panacea, they can, especially when installed in frequently used fixtures, cut household energy usage significantly.