Here is more than you ever wanted to know about night lights,
generated in less than 10 minutes :)
Having bought a number of neon bulb sort of night lights some years
back, and being pleased with their 0.25 Watt power consumption, and
extremely simple design (one resistor, in series with a neon bulb,
and enough plastic to hold them together with a plug that fits a
standard electrical outlet) which results in high reliability, I
went looking for more of them. I found several on-line
catalogs mentioning them, but all the stores were out of
stock. I perused all the stores that sell electrical
components in the admittedly small town in which I live, but which
perusal did include an Ace Hardware, a Home Depot, and finally, a
WalMart. And it was only at the latter that I found what
appears could be an acceptable alternative.
The new night lights I bought at WalMart, the Intermatic L.E.D.
Swivel Night Light, 2 pack, 0.1 Watt power consumpetion, seem to
provide more light than the 0.25 Watt neon bulb sort of night
light.
While it provides more light, the hood allows the light to be
directed down so that it is not annoying, and provides good
visibility for walking around at night.
While I am unsure of the internal complexity of the circuitry, and
the longevity of the device (although it is guaranteed for 7 years)
compared to the extreme simplicity and smaller size of the neon
bulb sort of night light, since I can't find the neon bulb sort
anywhere in town, this seems like a reasonable alternative.
The only lower power consuming night light I am aware of is the
"limelight" sort of thing, and I don't think they last long enough
to be worth buying. (apparently this is not a universal opinion, see
WikiPedia
Electroluminescence) they consume as little as 0.03 Watt,
however, and provide a warm, though faint glow.
Note that any night light with a sensor to turn it off when other
light is available is a gimmick: the incandescent bulbs generally
consume 1 - 4 Watts of power, so turning them off seems like a good
idea... but turning them on and off repeatedly (and you've likely
seen them flicker rapidly in low light) reduces the lifetime of the
bulb. Further, the sensor generally consumes as much or more
power than the "always on" neon bulb sort of night light! So
one is better off with leaving the night light on all the time, if
one uses low power night lights such as the neon or L.E.D.
varieties. Note that there are L.E.D. night lights on the
same shelf in WalMart that consume up to 0.5Watt. While I
didn't compare them for light output, the one I purchased, with a
rating of 0.1Watt, is plenty bright enough. It would appear
that the savings is mostly in the slightly lower purchase price,
which you pay for in 5 times the power usage (which likely is due
to a less efficient internal power supply). Your electric
rates would determine if the higher price is really worth it over
the lifetime of the product. At $0.10 / Kilowatt Hour, and a
7 year lifetime, the savings between a 0.1Watt device vs an 0.5
Watt device works out to $2.45. So that means you could pay
up to $2.45 more for the more efficient device, and come out ahead
in the end. Since the 0.1 Watt device only cost $2.55, it
would appear that the 0.5 Watt devices are only a bargain if they
cost less than a dime! Unless your power costs are
significantly cheaper than $0.10 / Kilowatt Hour (then they would
be worth more), or if the more efficient device actually lasts past
its warranty period (then the less efficient device would be worth
less). My light, purchased in December, 2003, are still doing fine.