A reader brings our attention to this free online TVA energy audit. It's fairly detailed, and the more information you provide the better recommendations it can make.

We came out pretty good, but there are more things we could do that would result in 10% to 20% more savings. As a wild guess, the payback would be about 10 years, but conservation is a good thing, too.

Here's the breakdown of our annual energy use:

Electricity:
Space Heating 1%
Laundry 3%
Kitchen Appliances 3%
Refrigerators/Freezers 4%
Small Appliances 5%
Lighting 8%
Home Office 18%
Air Conditioning 19%

Gas:
Other Usage 1%
Water Heating 4%
Space Heating 35%

I was surprised by how much the home office uses. But working from home and telecommuting offsets that in many other ways.

You can enter up to 12 months of utility bill info, but I put in just two, one for August and one for February. It did a pretty good projection on the other months based on that. Anyway, have a couple of utility bills handy when you start the survey. (P.S. The survey asks for gas consumption in "therms." Ours is billed in CCF. The conversion factor is 1 CCF = 1.0250 therms. Or you can just enter the CCF and it's close enough.)

Bonus: If you register and complete the survey, TVA will send you an energy conservation kit that includes two compact fluorescent light bulbs, outlet and light switch gaskets, filter whistle, two faucet aerators, hot water temperature gauge, home thermometer, and a "How to Save" brochure. (Through June 30, 2008, while supplies last.) That's a pretty good deal.

UPDATE: A reader writes "You can also call your utility (in the case of KUB, 524-2911) and they can give you your bill history right over the phone so you can get a complete picture of your consumption and thus get a more accurate report."