Many of us assume that if we want our clothes as clean as possible, we need to set our washing machines to use hot, or at least warm, water. That’s no longer true, though, and detergents designated as cold-water detergents are designed to get your clothes just as clean as with hot water. Since nearly 90% of the energy a washing machine uses is for heating water (according to the folks at Energy Star), you can save a lot by switching to cold water. The Department of Energy has noted that, “Using warm water instead of hot can cut a load’s energy use in half, and using cold water will save even more.” Cold water can even help clothes last longer.