Russell,

On Wed, 09 Feb 2005 12:10:17 +1300, Russell McMahon wrote:

>...<
> Note that CFLs save money on energy ONLY if you do not=20
> have thermostat controlled heating. Any time you use a=20
> thermostatically controlled heater energy sources such as light bulbs=20
> contribute to the heating and reduce heating power costs=20
> proportionately.

You're making some hefty assumptions here:

1. That heating is electrical, so costs the same regardless of the device=
 supplying the heat.  Mains-fed gas=20
heating is usually much cheaper (ironic, since electrical heating is 100%=
 efficient in itself - all of the=20
energy turns to heat, which is what you want! :-)
2. That heating is always used (whenever there are lights on), ignoring t=
he time when the temperature is fine=20
without heating, and that air-conditioning isn't used.  As soon as you ad=
d air-con to the equation it turns=20
round dramatically, because you are paying for the electricity to create =
the heat, then paying again to=20
extract it from the building.

I realise you're from a similar climate to me so heating is what you thin=
k of, but if you look at somewhere=20
like Southern California the time of maximum electrical demand is high su=
mmer due to air-con.
=20
> Electricity costs about $NZ1 per watt per years continuous operation.=20

Good grief, that's cheap!  Can you send some to me and we'll split the di=
fference?  :-)

I'm on a split meter, 7 hours overnight "cheap" at 3.09p/kWh, 17 hours at=
 12.84p/kWh.  That comes to 7.895p +=20
79.67p =3D UK=A30.876 per watt per year or NZ$2.32 or US$1.63 at today's =
exchange rates (this is without tax, and=20
without volume discounts).  If I was on a single rate meter it would be d=
earer, at UK=A30.95 (NZ$2.53, US$1.77).

I hadn't realised we were being fleeced quite so much!

As for the CFL discussion, I don't have any lights on 24/7, but several o=
n for 8 to 12 hours a day, depending=20
on the time of year.  I've been doing this for some years, since the orig=
inal Philips units came out, that had=20
a tough glass cover over the tubes (and they weighed a lot!).  Those last=
ed for about 4-5 years.  Being in a=20
cold environment (garage, unheated room) seemed to cause them problems, w=
ith failure to strike being a common=20
failure mode (flicking the switch repeatedly would usually get them going=
) .  The more modern ones with=20
exposed tubes, and some with a decorative globe cover, seem to last at le=
ast as long.  I must start recording=20
when I start using each one, so I'll know for sure!

Prices of CFLs vary dramatically here, from about 2.5 watt-years' cost to=
 about 4 times that, with no obvious=20
reason for the difference.

Cheers,



Howard Winter
St.Albans, England



--=20
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