Compact fluorescent lightbulbs have come as far as cell phones since the mid 80’s while still maintaining their high efficiency. What that means is:
If every one of 110 million American households bought just one CFL bulb, like this dimmable CF Warm Glow
Lightbulb, took it home, and screwed it in the place of an ordinary 60-watt bulb, the energy saved would be enough to power a city of 1.5 million people. One bulb swapped out, enough electricity saved to power all the homes in Delaware and Rhode Island …
In terms of oil not burned, or greenhouse gases not exhausted into the atmosphere, one compact fluorescent lightbulb is equivalent to taking 1.3 million cars off the roads … That’s the law of large numbers — a small action, multiplied by 110 million.
The single greatest source of greenhouse gases in the United States is power plants — half our electricity comes from coal plants. One bulb swapped out: enough electricity saved to turn off two entire power plants — or skip building the next two. (Fast Company)