Most people don't realize how much electricity a refrigerator uses. Unlike most household appliances, a refrigerator is working hard all the time. It is a heat pump, pumping heat out of the freezer, and using a fan to cool off the refrigerator unit. So, if you want to save money on your utility bill, you should make sure that your refrigerator is running at top efficiency.

The more efficient your refrigerator is, the less energy it will use. And that, of course, saves you money. Sometimes, the best way to make an old refrigerator more efficient is to simply get rid of it, and replace it with an Energy Star compliant new model. The savings on your electric bill can be substantial. Additionally, features such as automatic defrosting consume electricity as well. Modern designs are more energy efficient, and so replacing an old refrigerator almost always makes a great deal of sense.

Of course, whether your refrigerator is new or old, there are always other things that you can do to improve its efficiency. Is your freezer full? It should be. A full freezer is easier to keep cold. Filling milk jugs with tap water about two thirds the way up will eventually provide a nice block of ice that will help keep your freezer cold with minimal use of energy. And, in case of a black out, the jugs of frozen water will help keep other things in the freezer cold longer. Best of all, in case of a severe emergency -- think hurricane season -- the jugs of water can be thawed out and used. Remember, when you fill up those jugs to put in the freezer, don't fill them all the way to the top. Water expands when it freezes. Two thirds full should be just fine.

Speaking of water, open water evaporates and condenses in a refrigerator. This makes the refrigerator work harder, and also tends to drip little annoying drops of water on your hands whenever you reach for something on the top shelf. So, if you put something wet into the fridge, make sure it is covered.

Another handy method of making your refrigerator more efficient is to use the "energy saver" setting on your refrigerator's controls. The controls can be found on the inside of the refrigerator unit, often on the refrigerator's "ceiling." Try different settings, and be sure to use a refrigerator thermometer to make sure the settings keep your food cold, between 35 and 37 degrees fahrenheit, or around 2 degrees celsius. While you're at it, get a freezer thermometer as well. The freezer should be around 0 degrees fahrenheit, -18 celsius. Check both thermometers regularly, particularly during the summer.

When opening the doors to your refrigerator and freezer, make sure you've already got a pretty good idea what you're looking for. Keeping the door open while you "take inventory" is a bad habit that you should try to break. Know what's in your refrigerator, and where it's located. Refrigerator and freezer doors are kept closed with magnetic strips. The magnetic strips are embedded in a rubber seal around the door. Keep the seals clean. Debris on the seal can let air in and out, compromising the air tightness and making the refrigerator work harder.

You can test for good seals by slipping a dollar bill in between the door and the fridge. Close the door, and try to take the dollar bill out. If it's easy to remove, your seals need cleaning. After cleaning, try using silicone spray to revitalize the old rubber on the seals. If this doesn't improve things, you might want to see if you can get the seals replaced. You can order replacement refrigerator seals online, or by phone, from your refrigerator's manufacturer.

Bob Vila recommends that you put replacement seals in the clothes dryer for a few minutes to warm them. Warming, he says, removes the crimps that come from being packed in the shipping box. And while your keeping the door clean, be sure to vacuum around the coils. The refrigerator coils are usually either on the back of the unit, or on the bottom of it. The coils are essential working parts of your refrigerator -- they are how the refrigerator dissipates the heat that it is pumping out of the interior. Dirty coils don't dissipate heat well, because the dirt acts like an insulator. Clean coils do what they're supposed to do -- dissipate heat at maximum efficiency.

These simple maintenance tips should make your refrigerator live a healthy, energy efficient life. And you'll notice the difference on your utility bill.