Is your old fridge working optimally? Tips on saving electricity in the kitchen

Unless your refrigerator is so old or inefficient that you've already decided to replace it with a new ENERGY STAR fridge, it's a good idea to do a simple test to see if the refrigerator is running well. Issues like how often and for how long the compressor runs, whether there's frost build-up in the freezer section, how good your door seals are, and the temperature of the freezer and refrigerator compartments, can all affect your fridge electricity use.

Begin by simply trying to remember how often you hear the compressor churning. Does it seem to be running all the time, or is the fridge for the most part quiet? Does the motor appear to keep switching on and off (short periods of activity, then short rests)? During times of the day when the fridge door stays closed (for example between meals), the pattern of energy consumption for energy saving fridges is typically that of short periods with the motor working, followed by much longer periods of the compressor resting. If that's how your fridge behaves, you're off to a good start.

If the compressor is going nearly all the time, there may be issues with the gasket seal, or cobwebs on the coils, or the fridge may be in a closed-in area so that the heat the motor is working to extract from the inside has no place to escape to. You may just have an old fridge with an inefficient compressor motor, which translates into less heat extracted for a given electricity consumption, or you might have poor insulation, so that more heat leaks in through the refrigerator sides. Or you might have set the temperature too low in either the refrigerator or the freezer section.

Next look for ice build-up in the freezer section. Fast or heavy frost build-up in a manual-defrost freezer is usually a sign that warm, moist air is getting into the freezer section. You might have a bad seal on the freezer door, which allows cold air to escape between the gasket and the door, and warm, humid air to enter in its place. It takes more power to extract heat from moist air than from dry air, so you save in two ways by minimizing air leakage. Even if you have a perfect seal, you should defrost a manual-defrost freezer frequently. Do not let more than a quarter inch of frost form on the freezer walls, as it makes the motor work harder.

Check your refrigerator and freezer section gaskets to make sure you have a good seal. The standard test is the dollar-bill check. Open the fridge or freezer door enough that you can slide a dollar bill partway in, then shut the door. If the dollar bill is held tightly in place, the seal is fine in that section of the gasket. Do the same at several other points along the door seal. If at any point the bill slides out, or moves freely, try sliding the bill along the seal up and down until it stops. That should give you an idea of how big each leak is.

You can occasionally solve gasket leaks by wiping down the gasket to take off any bits of food residue that might prevent a good seal. But if there are gaps and the gasket is clean, you really need to replace the gasket.

Your fridge may pass the dollar bill test even though air is getting in - if the gasket is cracked. Cracks can develop in the thin part of the gasket where it is attached to the door. Run your finger along the gasket and check for tears, all the way around each door.

If you are a do-it-yourselfer, gaskets can be relatively cheap to replace. I bought a new gasket for my fridge a few years ago and with no previous experience had it installed within a half hour. And an appliance repair person can install one even faster, especially if you let them know to bring a replacement gasket with them when you call them. So if your gasket is leaky, get it replaced.

What are the proper temperature settings for your refrigerator and freezer sections?

The last item to look into in your do-it-yourself refrigerator assessment is the temperature inside both the fridge and freezer sections of your refrigerator. You can use either a standard glass thermometer or an electronic probe thermometer to check temperatures. Place the thermometer (or the probe portion, for an electronic thermometer) in a jar half-filled with liquid (a pickle jar works well), and leave it in the compartment for a full 24 hours. (Make sure the jar is only half full for the freezer section, so the freezing doesn't break the jar. Avoid opening the unit for at least an hour before you do your 24-hour measurement. Note the temperature on the thermometer. For the refrigerator compartment, you should try to achieve 39F or 40F (or 4C). For the freezer temperature, strive for 5F (or -15C). If the fridge temperature or freezer temperature is lower than this, you are wasting electricity cooling your food more than you need to.

Remember that for chest or full upright freezers, where frozen food tends to be kept longer than in the freezer compartment of refrigerators, you should strive for a somewhat lower freezer temperature of 0F or -17C.

If the temperature is not at the correct setting, adjust the thermostat in the appropriate section upwards or downwards by just a small amount. Then wait another 24 hours and take another measurement. It's best to adjust a little at a time, until you achieve the ideal refrigerator temperature. Once you reach that ideal setting, you can use a permanent felt pen to draw a line on the thermostat dial, so you have a reference point. There's no guarantee that this will always give you the ideal temperature (thermostats can be temperamental) but if you subsequently notice that the mark is far from the front, you'll know to measure the compartment temperature again.

It's important to check your refrigerator temperature (both compartments) regularly, or at the very least, if you have already checked it and have marked the position of the dial, to check that the dial hasn't moved. It's easy for these dials to get turned accidentally, or on purpose by little hands, and if the temperature moves far from the ideal settings of 40F for the refrigerator compartment or 5F for the freezer compartment, you will either have to deal with food spoilage or a higher utility bill.