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Refrigeration
Most people don't think of their refrigerator as being a big contributor to the home's energy bill, but in fact it is the third largest energy consumer in most homes, right behind space conditioning and water heating. They are usually between 6 and 16 percent of a home's total energy cost. Like air conditioners, refrigerators and freezers use the vapor-compression cycle to remove heat from a sealed and insulated containment box and exhaust it into the surrounding air.
Today's refrigerators are more efficient than older models. Improvements have been made to the containers, like better door seals and more insulation, as well as to the systems that move heat, including more area of heat exchanger, and improved controls, motors and compressors. Refrigerators with 15 to 20 percent higher efficiencies are available and may be cost effective depending on the utility rates. Be sure to look for EnergyGuide labels to see how many kilowatt-hours (kWh) the refrigerator or freezer will use in one year, and compare models based on these figures. There is a wide range in the energy use between models of refrigerators, so it's worth looking into carefully. Paying a little more for a unit that costs less to operate may be one of the best investments you can make. Also look for the ENERGY STAR® labeled units, which exceed federal efficiency standards by at least 20%.
Refrigerators with freezers on top are more efficient than those with freezers on the side. And chest-type freezers are 10-25 percent more efficient than upright cabinet models. This is partly because they are better insulated, and partly because they don't allow air to pour out when the door is opened. Also look for good strong door hinges that create a good door seal.
Improvements
Short of replacing your current refrigerator or freezer, there are plenty of improvements you can make to your existing unit. First, check door gaskets to be sure they are sealing properly. As they age and wear, they are less able to do their job of keeping cool air in and warm room air out. This requires the unit to run unnecessarily, wasting energy. There is a simple test to see if your seals are sealing properly. Place a slip of paper or dollar bill at the place the door closes, then close the door and pull on the paper. If it slips right out, the seal should be considered for repair or replacement. (If your door seals are magnetic, the test may not work.) Replacing door seals can get expensive, and if your unit is older, it may be time to look at just upgrading to a new energy-efficient model.
When you get a new refrigerator, it is tempting to move the old one to the garage or basement for extra refrigerated storage. This usually is a bad idea because older refrigerators can turn into big energy wasters. They are already probably less efficient units than your new model, plus their seals are wearing out, and often they are placed in a hot, unconditioned space where they have to run full time to keep their set temperature. Many a high electric bill complaint has stemmed from a second refrigerator quietly robbing from your energy budget at really marginal added convenience.
Refrigerators requiring manual defrosting use less energy than automatic defrost models, but that may be a small consideration compared with the convenience of not having to empty and defrost the unit. Another advantage of manual defrost unit is they are not as likely to cause freezer burn. Automatic defrost freezers tend to dehydrate food increasing freezer burn.
Check the inside temperature of your refrigerators and freezers with a thermometer because the ones built in aren't always accurate. A setting 10 degrees lower than recommended can raise operating cost by 25 percent. The refrigerator compartment should be between 36 ° and 38°F, and the freezer, between 0 ° and 5°F.
Most homeowners are not aware that there is a small switch located at the back of their refrigerator that can save them money. Automatic defrost refrigerator freezers use little heaters built into the refrigerator's walls to prevent moisture from condensing on the surfaces inside the unit. Some newer units have energy saver or power-saver switches that can deactivate these heaters when condensation is not much of an issue. Unless you have a condensation problem, keep this switched off.
Regular maintenance of refrigerators and freezers includes defrosting manual defrost units and making sure heat exchange coils are kept clean and have good air flow.
A full refrigerator or freezer operates more efficiently than an empty one. This is because when the door does open, if it is full, there isn't much area where warm air can enter. You can fill empty spaces with containers of water, which in a freezer has the added advantage of being able to hold a lower temperature in the event of a power outage.
Food should be covered prior to being placed in a refrigerator or freezer. Uncovered, moisture in the food will be evaporated into the interior of the unit causing it to use more energy. And don't put hot food directly into the refrigerator or freezer. Let it cool a little first, but don't leave food standing around too long either because bacteria grows well in unrefrigerated food.
