Updated 2/20/2020. I am starting to redo this.
There are some old and some new low wattage lights and night lights out there. I just want people to beware of possible disappointments and to know of some of the better ones.
Note that all models described below are made for use in USA or North America, and require 120 volts, and may require specifically 60 Hz AC. Most 120VAC LED models and in general 120 VAC electroluminescent models will work safely at 50 Hz 110-120 VAC with slightly reduced light output. Most fluorescent models requiring AC should only be operated at their rated AC frequency/frequencies.
Contents:
The usual 1/4 watt neon night lights
"Limelight", "Indiglo" and other electroluminescent models
GE, Dollar Store and Similar single-LED Nightlights
Some LED Nightlights that I Like
LED "lightbulbs" in general
UPDATE 4/1/2004 - These are less common than they used to be and are often now called "guide lights". They are available at Target and some/most places where GE nightlights are sold.
As for efficiency? The efficiency is comparable to incandescent, and the light output is comparable to the usual 1/4 watt orange neon models. But the light is mostly of wavelengths that night vision is sensitive to, and these illuminate dark rooms much more than 1/4 watt orange neon models do.
These do have impressive warranties against burning out. But there is one dark side of electroluminescent night lights: They do deteriorate with use. I have no hard figures, but I hear horror stories about their "half life" being only a couple to a few years. Sometimes their light-emitting areas develop dark spots.
NEWS 1/10/2004, updated 1/16/2004 - I purchased late in December 2003 a few LED nightlights from a dollar store. Claimed power consumption is usually 1/3-1/2 watt. Actual power consumption so far in my experience has mostly been around .3-.33 watt.
Most of the power consumption in these models is in circuit components other than the LED.
The white versions will fade over the years, with a "halflife" of only a few years or more likely even around a year, due to phosphor degradation that is normal in white LEDs.
There is a green version that both outperforms (in terms of illumination as seen by night vision) and outlasts the white version. There is also a blue verson.
White, green and blue units are brighter than neon and electroluminescent units, though dimmer than 4 watt incandescents. White, green and blue LED units stimulate night vision well and allow most people to easily see in rooms at nighttime.
Red and yellow LED nightlights are less common, since they are dimmer than white and green ones and also do not stimulate night vision well. Yellow ones are a little brighter than neon "guide lights", while red ones are about as bright as neon "guide lights". Red ones often effectively illuminate rooms even less than neon "guide lights" do.
A review is available HERE in Craig Johnson's world-famous site for LEDs and LED products, mostly flashlights.
GE produces a similar white LED nightlight, which I believe these are a knockoff of.
This is an LED "bulb" that can be used in place of 4-7 watt candelabra screw base incandescents. Power consumption is approx. .45 watt. Light output is fairly usual for LED nightlights. It has 3 white LEDs that have a very cool bluish white color. I estimate the color temp. to be about 8,000-9000 K. Light output is somewhere around "crude measurement" 1-2 lumens. Efficiency is in the "low end of incandescent" range, though better than that for night vision.
A shade is unlikely to be necessary in a usual candelabra base nightlight. The light output pattern is different from that of incandescents, due to the light output being more through the tip of the bulb. However, there is no well-defined beam.
The LEDs are being provided much less power than usual, so they should fade more slowly than most low power white LEDs do. As a result, I consider the claim of 50,000 hour life expectancy to be realistic.
2. Amertac Green/Blue switchable model 71381, available at Home Depot:
This is an LED model that resembles electroluminescent ones. Power consumption is stated as .3 watt. It is somewhat brighter than electroluminescent units. It has a switch for green, blue and off. It is available in 2-packs at Home Depot.
Although this unit provides less light than 4-7 watt incandescents, it is plenty bright for most nightlight use since green and blue LEDs provide wavelengths of light that night vision is sensitive to.
Light output in lumens so far, according to actual measurements although likely to not be very accurate, are approx. .2 lumen for green and approx. .1 lumen for blue. Although the photometric energy efficiency is less than that of incandescents, these lights can easily replace incandescent nightlights and achieve energy savings, since their light output is likely to be adequate with the high sensitivity of night vision to the wavelengths produced by these and most other blue and green LED nightlights.
To night vision, the blue LED used here actually outshines the green LED despite lower photometric results.
I consider this unit notable for being reasonably economically priced for a non-dollar-store unit, and also for having blue/green LEDs instead of an aging-prone white LED. Expect the LEDs to give many years of service with little fading.
Units of Philips brand (available at Home Depot) or Sylvania brand (available at Lowes) appear to me likely to be better and more honest with their ratings.
Buyer beware of any or any combination of the following disappointments in many models as of 3/29/2011:
* Light output claim has a big number due to apples-to-oranges comparison
(usually from the LED one having a beam)
* Light output is less than claimed by all measures
* Light from white units has an icy cold color
* Warm white version is even dimmer than icy cold color version
* Many white units will fade over the years
* White units have reduced efficiency if color rendering index is high.
This situation is not as bad now as it was in 2005-2009.
Beware that it is common for white LEDs to fade significantly within 10,000 hours. Better units are generally rated 15,000-35,000 hours, 50,000 hours at most.
If you see a life rating of 100,000 hours, then that is likely only the often-repeated number that applies for colored LEDs, and actual life expectancy may be much shorter.
Green units will tend to work well for good illumination efficiency and lack of fading. Red and blue units also resist fading, but generally provide less illumination. However, colored units are not commonly available except from online sellers.
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