The average household will spend $6,400 on utility bills and at the gas pump this year—$1,700 more than just two years ago, according to the Alliance to Save Energy. But you're far from powerless.

As a general rule, energy-efficient options cost more up front, but you'll often recoup the dollars in lower utility bills over the product's lifetime. (That's not always the case, as our report on tankless water heaters details.) The figures in this calculator are based on national average energy and water costs using typical examples from our tests and estimates provided by the American Council for an Energy-Efficient Economy.

Thinking of saving energy by replacing appliances? Start with the oldest, least-efficient units—and start before they break down as it's difficult to make a reasoned decision when you're faced with a broken furnace on a cold night. Even if you don't need new appliances, check out 25 simple ways to save. Some of the tips take just a minute.