Don Klipstein wrote:
I, Don Klipstein, need to correct my cost-per-1,000 hour figures for
CFLs, since I erred in a way unfavorable to CFLs.

It turns out I don't always do math well when my stomach is empty
and I smell dinner cooking.

The CFL cost figures below are correct if the CFLs last 1,000 hours
instead of 4,500 hours. The correct figures if they last 4,500 hours
are $3.50 per 1,000 hours less. The incandescent figures below are
still correct.

In , I, Don Klipstein wrote in
part:

o Comparative cost of each type, based on energy consumption and
lifespan

Using 11 cents per KWH:

60 watt "standard" 870 lumen incandescent lasting 1000 hours and
costing 85 cents:
$7.45 per 1,000 hours

75 watt 1100 hour 800 lumen 3-for-$1 dollar store incandescent:
$8.55 per 1,000 hours

75 watt 750 hour 1190 lumen 85-cent one dimmed to 800 lumens (65
watts, roughly 3000 hour life expectancy):
$7.43 per 1,000 hours

75 watt 750 hour 1190 lumen 85-cent one dimmed to 870 lumens (67
watts, roughly 2200 hour life expectancy):
$7.75 per 1,000 hours

13 watt CFL, costing $4.50, if it lasts 4500 hours, 800 lumens on a
good day:
$5.93 per 1,000 hours

I should have said $2.43 per 1,000 hours.

18 watt CFL, costing $4.50, if it lasts 4500 hours, 1100-1200 lumens
on a good day and usually exceeding 900 for practical purposes:
$6.48 per 1,000 hours

I should have said $2.98 per 1,000 hours.


Brilliant, (blast, didn't mean a pun), but to thank you for the correction.

An aspect that I have not seen any maths for is the amount of mercury that
has to be recovered/ disposed/lost through broken lamps compared to the
amount of mercury that would be emitted into the atmosphere through
combustion of coal for use of candescents.