Does an automatic shutoff energy saver light switch exist?
My parents always yelled at us to shut off our lights constantly and now I
find myself constantly yelling at the kids to shut the lights off. I know
it's a losing cause.
Maybe there is a better way?
Do they have automatic-shut-off light switches I can simply remove and
replace my existing standard light switches is? Are they inexpensive enough
to be practical?
Better yet, do reasonably priced light switches exist that automatically
turn the lights on and off as you walk by? Do they also fit in the existing
light switch boxes?
They work fine and the time left on after motion detected on most are
They exist. And they exist in a wide price range from low-end units
available at every big-box homecenter up to sophisticated high-end
commercial units. I have a few low-end units, one in my garage, one in
the entry hall from the garage, and one in the laundry room and have and
no problem with any of them unless you include a seeming unwillingness
to work with a CF-only load. The size is the same as a typical light
dimmer and they fit fine in a standard box but be forewarned that they
seem all to be compatible with "Decora" plates like you see with GFCI
outlets, not regular toggle switch plates. Whether they are worthwhile
depends on what your electricity costs, how often you leave the lights
on in an unoccupied room, what the lighting load is, and what you have
to pay to obtain and install the switch. I can't recall what I paid for
my switches but it seems likely that it must be < $20 given how cheap I am.
I have a timer switch
(www.intermatic.com/images/instruction_sheets/158ei12087.pdf) that I
got at Lowe's that works fine with a CF-only load. It does require a
I wish I could find a motion-detector switch that would work here. The
ones I have are 2-wire , and don't work with the CFs.
On Sun, 21 Jan 2007 23:05:48 GMT, Michael Balarama
My foray in this started when I figured out my wife and kids were
using the refrigerator as a night light in the kitchen. I took a
garden varirety motion detector head and hooked it up to a small light
in the kitchen (now rope light in the toe kicks and over the uppers.)
As the idea caught on I added motion sensors and occupancy sensors.
Now the lights follow you around the house, inside and out and go out
shortly after you leave, Don't let those PAR38 flood lights confuse
you. These can be hooked up to any sort of light you want. For
"walking around" light a fairly small amount of indirect lighting is
plenty. Spend your "watts" on task light where you need it.
BTW the difference between a motion sensor and an occupancy sensor is
a motion sensor is a "one shot" that times out and has to be
retriggered. An occupancy sensor gets retriggered on the fly and will
not time out until there is no more motion over the given period..
They do have Decora occupancy sensors.
Take a photocell and connect it to a timer, and connect the timer to a
very loud alarm that can be heard for miles, such as the ones that
cities use for tornados. It works like this. The photocell senses
the light which turns on the timer. If the timer runs for lets say 10
minutes, it flips on the alarm. That alarm will deafen anyone nearby,
and not only the kids know they are about to get the worst spanking in
history, but you are alerted that you need to arm the electronic,
remote controlled spanking paddle, which of course has electronic
sensors built in, so that it delivers the most painful spanking but
without leaving any permanent scars or bruises. When all is complete
and done, consider this: The electricity saved by shutting off the
lights is used to spank the hell out of the kid that left the switch
on. This is the ultimate in justice.
I must say this. Since your parents had to yell at you for not
turning off lights, and your kids are doing it now, this proves it's
hereditary. You passed this harmful and wasteful gene onto your
children. Remember this as you spank them, and be sure you place
yourself in the spanking machine after the kids are well done or
beaten raw. You too deserve a major whalloping.
On Sun, 21 Jan 2007 23:05:48 GMT, Michael Balarama
You know, some people want to make that spanking thing illegal. Maybe
they have a plan to control all of the juvenile delinquents that will
be created by prohibiting parents from disciplining their children
I have a question about turning lights on and off. I have been told
that leaving a light on maximizes its life and turning it on and off
frequently will shorten its life. Is this true? My background is in
transformers and it is better to leave them running than to shut them
off. Of course, we're talking about several thousand volts versus a
120V light bulb. Thanks.
Alfa Transformer Company
A tungsten filament lamp almost always expires the last time you turn it
on. (Sort of like why you always find something in the last place you
look.) The current surge in a cold filament and rapid expansion causes
the failure. The total time before this last gasp is probably about the
same even if the lamp is cycled on and off.
So if it were left burning, it's total hours would be longer than if you
had not turned it off, and then on, the last time.
Fluorescent lamps rely on a starter mechanism which degrades with use.
They may benefit from fewer on-off cycles.
As an aside, in the UK and other 240V lighting countries, an expiring
lamp will often cause a large enough "plasma arc" to take out the
circuit protection. Hence the lamps commonly include an "internal
fuse". This not needed at 120V.
Strange thing few people seem to realize about most incandescents - a
cold start does not cause much actual wear, but kills a filament that
would have survived a little longer if it was not turned off.
The usual cold start burnout is from a temperature overshoot in a thin
spot in the filament. The thin spot is a hot spot, and on a cold start
the thin spot can overshoot in temperature before the remainder of the
filament has warmed up. Resistance of the filament material varies
directly with temperature, so a thin spot overshoots in temperature
from the current surge before the remainder of the filament has full
resistance and the current drops to normal.
However, a thin spot is is hotter than the remainder of the filament
even during steady operation (but to a lesser extent than during a cold
start). The hotspot will evaporate faster and get thinner at a faster
rate, making it hotter and thinner. This downward spiral accelerates in a
manner worse than exponentially. By the time the thin spot cannot survive
a cold start, the filament's hours are numbered!
The bulbs also suffer actual wear from starting. How much life is lost
varies with the type of ballast and starting means and this has been
improved over the decades. I am under the impression that a typical
figure is 10 minutes of life lost per start.
As for how much off time is needed before the electricity saved from
turning off a fluorescent exceeds the fraction of the bulb's cost
associated with life reduction of a start - this varies with electricity
cost, bulb (lamp, tube, whatever) cost, and ballast and starting method,
but is typically a couple minutes for 4-footers, ballpark of 10-30 minutes
for lower wattages 9-22 watts, and ballpark of 30-60 minutes for wattages
8 watts or less.
My experience in the USA is that 120V gas-filled incandescent lamps often
have an internal fuse. In the USA that bright blue flash from a cold
start burnout is this "plasma arc". At 120V that arc tends to die at the
next end of a half cycle and some incandescents lacked this fuse and
usually got away with it, but sometimes things got nastier and one thing
that sometimes happened (I would guess mainly when this fuse was lacking)
was that wires between the glass bulb and the base would either fuse
explosively or vaporize adjacent glue - and the glass bulb pops from the
These "burnout arcs" sometimes also blow dimmers with the large amount
of current that they sometimes draw even at 120V.
- Don Klipstein ( email@example.com)
I've seen motion detector light switches at Lowes. I don't remember the
price, though. You set them for a certain delay, and after so much
non-movement, they shut off. What I'm looking for now is a humidity
activated switch that automatically turns on the bathroom fan when it gets
too steamy in there. :)
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