Although it may be hard to believe, in the average household the second most costly output is in heating the water.  Even more so than your central heating, *air conditioner*, or food costs, ensuring that your home has hot water is often an expensive requirement. However, a lot of this cost can be overcome, or certainly reduced, by simply ensuring you have the most cost-efficient water heater installed in your home. By combining the right water heater with more energy efficient devices, you should soon see the costs of your bills plummet.