Donna Summer didn’t have it quite right when she sang “Dim all the lights, sweet darling,” in her 1979 disco hit called “Dim All The Lights” (though installing dimmers can significantly cut your energy use, so says the National Geographic Green Guide). No, if you really want to save money on your electric bills, you’ve got to take a two-pronged approach, which our Lean Green Family has been doing and is living proof that this approach works.

First, train yourself (and your spouse and your kids and your pets–wait, my dog doesn’t have opposable thumbs so he can’t help in this regard) to turn off the lights and nearly every other electrical appliance in use when they leave the room and are done using it. Why? To save energy. I’m sure your mom told you the old saying, “The last one to leave, please turn out the lights?” Well, mom was on to something, and it’s a wise saying I believe we should pass on to our modern-day families.

Second, invest some time and money in removing all of the incandescent bulbs from your lamps and replacing them with compact fluorescent lights (CFLs). Sure, CFLs cost a bit more upfront but your pay off will come in the long run. Studies show that CFLs last 10 as long as traditional light bulbs, meaning a bulb you install in your living room today might not need to be replaced until 2012. At the same time, Energy Star says CFLs use up to 75 percent less energy than incandescent bulbs.

OK, so this sounds like a “yadda yadda yadda” commercial for light bulbs and whatnot, but here’s where the real-life proof of changing bulbs and turning off lights comes into play: yesterday, we got our PECO electricity bill. And since making the concentrated effort to change our lights and turn them off, our electricity bill has gone down.

This month, our bill was $153.00.

The month before that, it was $213.00.

As far as kilowatt use goes, this month we used just over 900 kilowatts.

The month before that, we used just over 1,350 kilowatts.

Except for a spike in August, when it was really hot, our kilowatt use has been going down steadily since we moved in six months ago.

I’m sure it’s helping now that, with cooler weather, we have neither our central air nor our pool pump running, but the bottom line is this: we’re using less energy and saving money to boot.

So maybe this year your holiday gift to your family, though not very sexy, should be a series of CFLs and a concentrated effort to make sure that if you are the last person to leave the room, you really do turn off the lights.