Tuesday, March 29, 2005


Freezers and Refrigerators..
ron thomas


Your freezer and refrigerator come under the heading of inefficient users of power because of the motors that drive their compressors. Remember that motor driven electrical devices are about 60% efficient with the 40% being lost to heat? Yet, modern day refigeration devices have improved their efficiency through better insulation of the box.

If we were to color the air inside the refrigerator or freezer so that we could see it when we opened the door we would see the air inside rapidly fall to the floor of the kitchen only to be replaced with warm air from the kitchen. Cold air is heavy and would fall out... warm air is lighter and rushes in to fill the void. You can see as soon as you close the door the refrigerator or freezer is going to turn on to bring the temperature of the new air down to where you have set its thermostat.


The more times we open our unit the more it will run and the more it will cost. Because the refrig/freezer is well insulated it will stay off longer if we don't open it. So if we change our behavior to know what it is we are after and try to keep it closed as much as possible we will realize a savings.


All that said, if you are thinking of buying a new freezer which would you think would be more efficient a chest freezer or an upright? If you answered a chest freezer you are correct. If you remember our above example about coloring the air and watching it slide to the floor when we opened the door of our upright refrig/freezer because cold air is heavier than warm air? Think now about opening the lid of the chest freezer. The cold air stays in the box because it is heavier. Therefore, this type of freezer is more efficient.

Since the insulation in modern freezers and refrigerators is more efficient than those of older days I am planning to experiment with placing a timer on them to cause them to stay off during the sleeping hours of the night and rely on that insulation to keep them within temperature parameters. The starting and stopping of the compressor motors on these units is pretty expensive....

Recapping, change your habits on how you get in your refrigerator or freezer as little as possible. Chest freezers run less than uprights. A timer to keep your unit off during sleeping hours may help but needs more experimentation.

A side note... if your units run all the time.. something is wrong. The gaskets are leaking or the unit is old and not cooling well do to a loss of freeon. Usually the cheaper course of action in this case is to buy a new one.. pay attention to its Energy Rating sticker if you do.



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