You don't have to install the newest energy saving water heater to get it into better energy shape. You can start by bundling your water heater in an insulating jacket, particularly if the heater was made before 1992. It will reduce the heat lost through the walls of the tank by 25-40 percent. These jackets work well on brand new water heaters as well as old ones, although they lead to more dramatic energy savings on the older models. Make sure you don't put a jacket on a model where the manufacturer says not to and make sure you don't cover the thermostat. In addition, don't restrict the air inlets.

Each 10 degree reduction in the water temperature setting on your water heater cuts the heater's energy consumption by 3-5 percent, so setting your water heater at 120 degrees Fahrenheit should be comfortable and more energy-efficient. Your dishwasher will still get dishes clean if it has an internal heater to finish heating the water to 140 degrees. If it doesn't have an internal heater, keep the water heater at 140 degrees.

When you go on vacation, turn the thermostat on the water heater off, or at least turn it down to its lowest possible setting. If your heater has a pilot light, make sure you know how to relight it when you get back. A couple of other ways to make your heater more efficient is to insulate your hot water pipes to reduce heat loss on the way to the tap. Put in heat traps or one-way valves in the pipes to cut loss, too. You should also insulate the first 3 feet of cold-water pipe connected to water heaters, too.

To prolong the life of your water heater, it is recommended that a water heater be drained and flushed every six months to remove sediments and check for rust and corrosion.

Most water heaters last 10-15 years. If yours is advancing in age, have a Sun Devil plumber look at it and advise you on how much life it has left. If it is starting to go (or is just very inefficient) it may make sense to replace it with a more energy efficient water heater now before you have a houseful of guests.