How Many Big Electric Bills Does It Take to Change a Light Bulb?

To conserve both energy costs and the environment from within your home, seek higher inspiration.

That is, look at your ceilings and contemplate the light bulbs screwed into the fixtures.

The Department of Energy estimates that the average household spends 11% of its energy budget on lighting. But if you're willing to trade in the incandescent bulbs that Thomas Edison developed in 1880 for newer innovations, you can knock those costs down by as much as 75%, enough to make a noticeable difference on your electric bill.

The most common replacements for conventional bulbs are compact fluorescents. Yes, they were once known for poor lighting and u-shaped designs that didn't actually fit in most fixtures. But General Electric(GE Quote), Philips Electronics (PHG Quote) and Siemens(SI Quote), among others, now make them in a range of sizes and shapes that are easily interchangeable with conventional light bulbs in lamps and ceiling fixtures.

Compact fluorescents aren't catching on as quickly as environmental advocates would like, primarily because of the upfront price tag. You can by a two-pack of standard GE 60-watt bulbs at Lowe's(LOW Quote) for $1.98. Compact fluorescents can cost two or three times as much, at least.

But it's not an apples-to-apples comparison. A 15-watt compact fluorescent will provide as much light as a 60-watt incandescent, which means the newer bulb uses a quarter of the power to get the same amount of light -- that's a 75% savings every time you flip the light switch.

Additionally, that compact fluorescent will provide 10,000 hours of light, while the conventional bulb will provide 1,000 to 1,500 hours. That means you have to buy six to 10 of Edison's old bulbs for every one energy efficient bulb you buy.

Put another way, you're spending $6 to $10 on incandescents for every $2 or $3 you would spend on the CFBs. One billion bulbs does a good job of showing how the costs add up.

For an assessment of your own home, Environmental Defense has a calculator that shows how much money and carbon dioxide you'll save by replacing your incandescent bulbs. Assuming I had conventionally sourced electricity, which is typically generated using a lot of fossil fuel, if I replace just four 60-watt bulbs with 15-watt energy-efficient ones, I can save about $500 over the life of those new bulbs and spare the atmosphere some 1,650 pounds of CO2.

Detractors of the compact fluorescent like to point out that there's mercury in them, which doesn't seem very green. Treehugger observes that each bulb contains less mercury than is generated by waste from the power plant firing up your incandescents. But the mercury often makes it illegal to throw the lamps in the regular trash and can cause a toxic mess, albeit a tiny one, if they break in your house. They usually can't be tossed in with the rest of your recycling either.

The Lighterfootstep blog argues that this is a smaller problem than it might seem when you remember that you only have to throw these bulbs out every few years, but it still poses a quandary. If these bulbs are going to become household mainstays, public sanitation departments will have to find a way to deal with them.