Fuel Price Pro

Robin Green asked:


Unless your fridge is so old or worn out that you’ve already chosen to replace it with an energy efficient fridge, you really should do a simple assessment of whether the fridge is running well. Issues such as how often and for how long the compressor motor runs, whether there’s frost in the freezer section, how good your door seals are, and the temperature range of the freezer and fridge sections, can all impact your refrigerator energy use.

Begin by simply trying to remember how frequently you hear the motor going. Does it seem to be going continuously, or is the refrigerator usually silent? Does the compressor seem to keep switching on and off (short periods of running time, then short rests)? During times of the day when the fridge door stays shut (for example overnight), the pattern of energy use for energy saving fridges is typically that of short periods with the motor working, interspersed with much longer periods of the compressor motor resting. If that’s how your fridge behaves, you’re off to a good start.

If the compressor motor 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 an enclosed area so that the heat the motor is working to extract from the interior has nowhere to escape to. You may just have an old refrigerator with an inefficient compressor motor, which translates into less heat extracted for a given amount of electricity input, or you might have substandard insulation in the fridge walls, so that more heat flows in through the fridge sides. Or you might have set the temperature too low in either the refrigerator or the freezer compartment.

Next look for ice build-up in the freezer compartment. Fast or heavy frost build-up in a manual-defrost freezer is usually an indication that warm, moist air is getting into the freezer section. You could have a poor seal on the freezer compartment, which allows cold air to escape through the seal, and warm, moist air to enter in its place. It takes more power to extract heat from moist air than from dry air, so you win on two fronts by eliminating air leaks. Even if you have a great seal, you should defrost a manual-defrost freezer regularly. You should never let more than a quarter inch of ice form on the compartment walls, as it makes the compressor motor work harder.

Check your refrigerator and freezer compartment gaskets to make sure you have a good seal. The standard test is the dollar-bill check. Open the refrigerator or freezer door so that you can slide a dollar bill halfway in, then close the door. If the bill stays tightly in place when you pull, the seal is fine in that part of the gasket. Do the same at several other points along the gasket. If at any point the bill slides out, or moves freely, try moving the bill along the seal in each direction until it sticks. That should give you an idea of how big each leak is.

You can sometimes solve gasket leaks by cleaning the gasket to remove any residue that might prevent a good seal. But if there are gaps and the gasket is clean, you really should replace the seal.

Your refrigerator may pass the dollar bill test even though the gasket is letting in air - if the gasket is cracked. Cracks can open up in the thin part of the gasket where it attaches to the door. Run your finger along the gasket feeling for rips, all the way around each door.

If you’re a DIY type, gaskets can be fairly cheap to replace. I bought a new gasket for my refrigerator five years ago and with no previous instruction had it on the door within a half hour. And an appliance repair person can install one even faster, especially if you tell them to bring a replacement gasket with them when you call them. So if your gasket is leaking or too rigid to provide a good seal, get it replaced.

What are the ideal temperatures for your fridge and freezer sections?

The last thing to look at in your do-it-yourself fridge assessment is the temperature in each compartment of your refrigerator. You can use either a standard glass thermometer or an electronic probe thermometer to do this. Place the thermometer (or the probe portion, for an electronic thermometer) in a jar half-filled with liquid (a pickle jar does nicely), and leave it in the compartment for a full 24 hours. (Make sure the jar is only half filled with liquid for the freezer compartment, so the freezing doesn’t break the jar. Don’t open the unit for at least an hour before you do your 24-hour measurement. Check the temperature on the thermometer. For the fridge compartment, you should strive for 39F or 40F (or 4C). For the freezer temperature, go for 5F (or -15C). If the refrigerator temperature or freezer temperature is lower than this, you are wasting energy cooling your food more than necessary.

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

If the compartment is not at the ideal setting, adjust the thermostat in the appropriate section up or down by just a small amount. Then wait another 24 hours and take a second reading. It’s best to tweak the thermostat a little at a time, until you reach the ideal refrigerator temperature. Once you reach that ideal setting, you can use a permanent marker to draw a line on the thermostat dial, so you have a reference point. It’s not a given that this will always give you the ideal temperature (thermostats can be finicky) but if you subsequently notice that the line is far from the front, you’ll know to measure the temperature once more.

It’s important to measure your refrigerator temperature (both compartments) on a monthly basis, or at least, if you have already checked it and have marked the position of the thermostat dial, to see that the dial hasn’t moved. It’s easy for these dials to get turned inadvertently, or on purpose by little hands, and if the temperature varies far from the proper settings of 40F for the fridge section or 5F for the freezer section, you either risk food spoilage or a higher electricity bill.