Economy question

It is a well known fact that it is more economical to leave a florescent
light

switched on that to switch it on and off when entering and leaving a room.

Ali...

Like many 'well-known facts', this is mainly a myth. It is also fairly
meaningless, unless some indication of frequency for entering and leaving a
room is give.

A short message from the University of Newcastle.

More detailed information:
According to
you would have to be switching on and off every 5 seconds or less for the
extra energy used at switch-on to exceed the energy saved by not leaving the
light on. So that would suggest always switch off the light when leaving a
room empty.

However, there is a second cost in switching on a fluorescent lamp: the
electrodes erode quicker. Again, according to the above site, the break-
even point for energy saving against tube wear is about 15-20 minutes burn.
In other words, turn the light out if it is going to be off for more than 20
minutes.

pmj...

& it's also a very often mis-represented (& mis-understood) "fact"!
:-)

The real "Facts" are that it all depends...

& you need to compare the Initial (higher) Consumption [*1], of them
(when they're first switched on) with the extra consumption caused
by leaving it on for excessively long periods.

[*1]
As well as the (slightly) shortened life of them, caused by each
Swicth on Surge.

My question is : does the same apply to energy saving light bulbs ??

pmj...

Yes, but to a *far* lesser degree.

Most "Energy Saving" type Bulbs (Lamps or whatever you want to call
them!) *are* Fluorescent, but the Control Circuitry is usually far
more efficient than the sort used in a normal Flouorescent Light
Fitting.

They don't use the normal sort of "Choke" & "Starter Switch" thing -
they use (High Frequency & thuis more efficient) Chokes & Capacitors
etc.

Having just fitted some around the house it would be useful knowing the

best way to use them.

Tickettyboo...

No sure, but I thought the reason for leaving flourescent ones on was
because they have a sort of 'starter motor' thingy, and that takes more
electricity to fire up than it would to just leave it running. Don't
'think' the energy saving ones have that?

Ali...

They do, in the base, but the extra energy used is negligible (about 5
seconds worth).

See my reply to Wally for more detail.

MCC...

I dunno about the economy Wally, but if I'm coming back into a room in a
relatively short period of time, I always leave the energy saving bulb on
because I hate the semi-gloom that they produce when they are first
switched on. They're fine once they are up to full temperature but, oh
dear, when they are first switched on.

Wally...

Yes, I did notice that, that is why I wondered if they where
useing more energy when warming up.

Ali...

implies that compact fluorescents follow the same rule are normal
fluorescents.

Also those two sites are american, and use a price of 5 cents per kWh.
Typical british prices are 7p or more per kWh

l has a table comparing total costs over 20,000 hours

For what it's worth, the light (a single compact fluorescent) in my main
room goes on at dusk and off at bedtime, whether I'm in the room or not (the
glow can be seen from the road so this is a securiy measure as well as a
convenience. Other lights only go on if I'm in the room, or expecting to
return very shortly.

pmj...

As with *all* forms of Energy Consumption - using them as little
as possible is really the best way!
:-)

But on the assumption that you have bought them *because* you do
actually want to have Lights on , then...

Use them when needed (& while in use, they will be saving *some*
Electricity, compared to ordinary (Filament, Incandescent) Bulbs).

But turn them off when they aren't going to be used for *long* periods.

If everybody (in the Country - & in the World) was to turn off Lights
when not actually needed, there would be *far* less of a problem with
Fuel Shortages!
:-)

& also far less of a problem with "Light Pollution" & "Light Scatter"
etc, in the Sky, so then we could actually *see* the Stars in the Sky!

andon...

Remaining seated certainly takes less energy Wally.

Flyiñg Ñuñ 2°°6 +...

None lost Wally, just not enough light given out.
Incandescent lamps also have a warm up period, but it's only milliseconds
rather than a few minutes, so you wouldn't notice it. :)

Aries...

now there's a thought ?

Old Grizzly...

Thinking of the energy needed to keep turning that switch off and on its
better to leave it on:)

Get someone else to go and switch the darn thing off.

Wally...

And sit in the dark ??? :o))