Scripko.org http://scripko.org A gathering of my thoughts and musings Mon, 21 Jan 2008 01:24:09 +0000 http://wordpress.org/?v=2.2.1 en Economics of a CFL. http://scripko.org/2008/01/20/economics-of-a-cfl/ http://scripko.org/2008/01/20/economics-of-a-cfl/#comments Mon, 21 Jan 2008 01:24:09 +0000 admin http://scripko.org/2008/01/20/economics-of-a-cfl/ Over the coming weeks, I am going to look at the economics of various “green” efforts.  My goal is to find the sources that actually save money, as opposed to items that cost more than their savings (a combination of difference in cost of machinery and energy savings).

To start with, I’ll do the CFL, widely regarded as something that saves major moolah on the electric bill.  Analysis as follows:

Cost of 1 CFL light bulb: $3.24 (bought in 4-pack for $12.99, 60-watt equivelent).

Lifespan of 1 CFL bulb: 9,000 hours (taking the middle of a 8,000-10,000 lifespan range)

Wattage used for lightbulb: 13W

Cost of one 60W Incandescent lightbulb: $0.49 (bought in 8-pack at Lowes)

Lifespan for one lightbulb: 2,000 hours

Wattage used for one lightbulb: 60W.

Math is indented so that people who don’t want to see it can gloss over it.

Then we do some math: 9,000/2,000 = 4.5 Incandescent light bulbs per CFL.
At this point, it costs $3.24 to use CFL, and (.49*4.5)=$2.20 to run Incadescant. In other words, we need to save $1.02 in electricity to make it cheaper.

9,000(60-13)= 423,000 wattshours saved (based on the 9,000 hour lifespan) = 423kWh (kilowatthours)

Cost per kWh = $0.09 (This obviously varies across the country)

Total electrical savings = 423 * 0.09 = $38.07

Total savings = (Material Savings) + (Electrical Savings) = -1.02 + 38.07 = $37.05

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