Night Lights and Energy Saving Low Wattage Lights - Test Results

Updated slightly 3/2/2008, with most info here much older.

There are some old and some new low wattage lights and night lights out there. I just want people to beware of possible disappointments. Please note that all models described below are made for use in the USA, and require 120 volts. Some models 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 frequency, however.

Contents:
The usual 1/4 watt neon night lights
The dual neon daylight-shutoff white oblong model
Those 3.5 and 4 watt fluorescent models
General Electric 1.5 watt fluorescent models
"Limelight" and "Indiglo" electroluminescent models
Black And Decker daylight-shutoff model
General Electric / U.S. Energy Technologies 1.5 watt Mini Guide Light
GE and Dollar Store LED Nightlights
Target roundish-oval LED Nightlights
LED "lightbulbs" in general

The usual 1/4 watt neon night lights

Most of you are probably familiar with these. They usually have a C2A (NE-2H) neon lamp and a 33K resistor. These do indeed draw 1/4 watt of power. The NE-2H neon lamp is rated to last 20,000 hours with 120 VAC and a 33K resistor. The neon lamp normally fails gradually, either flickering or becoming dim instead of suddenly burning out.

The NE-2H neon lamp is also rated for use with a 22K resistor to use 1/3 of a watt. However, the life rating drops to 5,000 hours. If you try to get really long life by hacking out the resistor and replacing it with one over 33K or adding additional resistance, you may be disappointed. Life increases only roughly proportionately with resistance as resistance is increased above 33K.

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 places where GE nightlights are sold.

The dual neon daylight-shutoff white oblong model

I don't like these. I don't know the brand of the ones I am thinking of, but they are white, approx. 3 inches (7.5 cm) wide, 7/8 inch (2.2 cm) high, and have an A1B neon lamp (shorter version of the NE2) in each end. I think these are too dim. In addition, power consumption INCREASES when the light is shut off by daylight or room light.

The unit consists of two A1B neon lamps and a 10K resistor all in series, with a cadmium sulfide cell in parallel with the pair of neon lamps. Another problem with this unit is unreliable light output at low voltages. This unit will not light during a significant brownout.

Those 3.5 and 4 watt fluorescent models

I have the 3.5 watt one by American Power Products. I hope other brand ones are better. These are generally claimed to be equivalent to a 20 or a 25 watt incandescent lamp. My 3.5 watt unit is dimmer than a 15 watt incandescent lamp - equivalent to or maybe slightly brighter than a 10 watt 120 volt incandescent lamp. I did allow the lamp to warm up before comparing it to incandescent lamps. The spectral output is slightly more favorable to night vision than that of incandescent, but even to night vision, my 3.5 watt light was dimmer than a 15 watt 120 volt incandescent lamp.

The American Power Products 3.5 watt unit that I have also flickers slightly.

General Electric 1.5 watt fluorescent models

There are at least three of these:

1. A very rounded triangular or triangle-egg-shaped one with a blue push-on-push-off switch, which glows an icy cold pure white to "daylight" color.

2. A different shape white one with a "1-0" switch, which glows a roughly incandescent yellowish warm-white color.

3. A green model which is labelled as "neon".

I purchased the yellowish-glowing model on July 1 2002 and the pure-white-glowing model on July 8 2002 and have been running them 24 hours a day ever since with few breaks.

The yellowish-glowing model produces more light than the pure white model, but to night vision it may be the other way around. The yellowish model produces approx. 9 lumens of light, which is a little less than half as much light as is produced by a typical 4 watt 120V incandescent lamp. To night vision, light output may be more than half that of a 4 watt incandescent. Efficiency is about that of 7-7.5 watt 120V incandescents. Miniaturized fluorescent lamps, especially when miniaturized in length, are inherently less efficient than longer ones.

No claims are made as to light output nor life expectancy except that life expectancy is longer than that of 4 watt incandescent.

UPDATE 5/7/2003 - The warmer color one burned out on 5/4/03, which is approx. 7400 hours. It has experienced approx. 100 starts.

UPDATE 4/1/2004 - The cooler white one largely conked out in mid-March 2004, with two distinct major decreases in brightness about a week apart. It lasted a little over 20 months of operation 24 hours per day with only a few hours per year of off time.

The yellower one and the pure/cool white one appear to have different circuits inside.

"Limelight" and "Indiglo" electroluminescent models

These work. They do indeed draw extremely small amounts of power. They are capacitive loads, so the power consumption is less than the figure you get by multiplying volts by amps drawn. (For further explanation, get almost any textbook that covers AC circuit analysis.) For more info on electroluninescent lamps in general, go to my odd lamp page. But these do indeed draw only 1/16 of a watt.

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.

Black And Decker daylight-shutoff model

These do work. Furthermore, the model I am thinking of (don't have a specific model number handy) has a diode built in to dim the bulb and extend its life. Light output is reduced about 70 percent, and power consumption is reduced by about 40 percent. However, the very thin filament cools significantly during the "off" half of each AC cycle and heats up significantly during the "on" half of the AC cycle. Life extension is less than one would expect, but still significant. The bulbs seem to last an average of roughly 5-10 years in normal household use.

General Electric / U.S. Energy Technologies 1.5 watt Mini Guide Light

I consider this one a disappointment. The package claims it draws 1.5 watts and puts out as much light as a standard 7 watt night light bulb. This may be true if you are comparing this thing to a 7 watt old-fashioned night light used with a black shade because a 7 watt bare bulb is too bright. Otherwise, I have a gripe with this claim. The Mini Guide Light produces about 40-50 percent as much light as a 4 watt standard night light bulb.

The bulb in the Mini Guide Light is a low voltage incandescent lamp that is built in and not intended to be replaceable. I could make out the filament, and think the bulb may be an 1829 or an 1819 or something similar. This light has a built-in electronic ballast to power a low voltage incandescent lamp. There is an efficiency advantage, since a shorter, thicker filament can be operated at a higher temperature for the same lifetime than a thinner filament can.

From the color of the filament, I expect a lifetime of at best several thousand hours. Since it costs about US$ 7 and could easily burn out in a couple years, I think it is no bargain.

Dollar Store and GE LED Nightlights

NOTE 3/2/2008 - similar products of other brands have appeared.

NEWS 1/10/2004, updated 1/16/2004 - I purchased late in December 2003 a few LED nightlights from a dollar store. As far as I can tell, they come in red and "icy cool white" (pure white to slightly bluish white). These consist of a plug-in small module that has a light-transmitting decorative plastic piece stuck into the module.

Look for a reddish hot pink "QC" sticker or a white "QC" sticker on the module between the prongs - it appears to me that the sticker indicates the light color. The red ones produce (estimated) 1/4 lumen of light, and the red light has low night vision impact and does not "knock down" high extent of "dark adaption". The white ones produce (estimated) 1/2 lumen of light, with "high night vision impact" - it is easy to see around a room by these once you are dark-adapted, but this amount of night-vsion-impacting light is excessive for those who require maintaining full dark-adaption. For most "normal" use the white versions are better.

For normal use, the white versions are much brighter than the usual neon types and the usual electroluminescent nightlight types, but dimmer than 4-watt and 7-watt incandescent types. The red versions are largely but not entirely comparable to brighter 1/4-1/3 watt neon nightlights.

Claimed power consumption is 1/2 watt. Actual power consumption is .32-.35 watt for white versions, presumably a little less (approx. 1/4 watt) for red versions, assuming no electrical components are different except the LED. A majority 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 even around a year, due to phosphor degradation that is normal in white LEDs.

There is a green version (with a green InGaN LED) that both outperforms (in terms of illumination as sensed by night vision) and outlasts the white version. There is also a blue verson. Their "QC" stickers are green and blue respectively.

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.

Target roundish-oval LED Nightlights

Target sold these nightlights, but discontinued them. They have since turned up at a small number of dollar stores, but mostly went away afterwards.

These are the ones reviewed by Craig Johnson as noted below. Target now sells other LED nightlights.

They are attractive, roughly of the shape and size of an egg, and have a round dome. Power consumption is claimed to be 1 watt. They have a photocell to shut them off when bright light is present, although the current draw (but possibly not the actual power consumption) does not change much when this happens.
Light output is much more than that of neon "guide lights" and somewhat more (only slightly more to night vision) than that of electroluminescent models, but much less than that of 4-watt incandescent models.

Craig Johnsom has a more extensive review of these at:

http://ledmuseum.thefire.us/tpnight.htm

One note: I have found these to noticeably lose light output and become more blue in color after just a few months of operation. I suspect the phosphor in the white LEDs is a lower quality one that fades from just a few thousand hours of operation.

LED "lightbulbs" in general

There are now many LED screw base "light bulbs". These have screw bases and fit in usual lightbulb sockets. Most have wattage 1.5 to 6 watts. Most have big claims of energy efficiency and/or "incandescent equivalence".

Buyer beware of any or any combination of the following disappointments in many, probably most models as of 3/2/2008:

* 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 has an icy cold color
* Warm white version is even dimmer than icy cold color version

Written by Don Klipstein.

Copyright (C) 2003, 2004, 2008 Donald L. Klipstein. Please read my Copyright and authorship info.
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