Which will save you more green when you're washing your clothes -- gas or electric?

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Buying a new household appliance is usually a long-term investment, whether you're replacing an old unit or setting up a home for the first time. Why not take advantage of the occasion to buy the most energy-efficient products you can? Before you buy a clothes dryer, though, you need to understand the difference between the two types that are most commonly available: gas and electric.

Both types of dryers function similarly -- air is drawn into the dryer, passes through a heating coil, warms the clothes inside, collects moisture, and is vented out. Gas dryers use gas to create the heat, and electric dryers use electricity. Both types use an electric fan to distribute the heat. Even though both types require a steady stream of electricity, gas models are slightly more efficient.

According to the Consumer Energy Center, the clothes dryer (whichever type you have) is the second most energy-hungry appliance in the house -- only the refrigerator uses more power. Dryers are measured by a standard called the energy factor, which measures pounds of clothes per kilowatt hour of electricity. (This standard is also used in a similar application: measuring the power usage of water heaters.) The energy factor's ultimate cost depends on current electricity rates, but the Consumer Energy Center says the average household will spend about $85 per year to keep its dryer juiced.

Shopping for a clothes dryer might be a little off-putting -- many models are available in both gas and electric versions, and unlike nearly every other type of appliance at your chosen electronics or home store, clothes dryers don't display those ubiquitous Energy Star placards. Energy Star is a voluntary label that spotlights the most efficient appliances in each class, but since all dryers have similar energy requirements, they don't qualify for the program. For that same reason, clothes dryers also are exempt from displaying the EnergyGuide placard (which is usually a requirement).

Don't stop reading here, though -- we'll discuss more differences between gas and electric dryers, as well as some energy-conserving alternatives.