Refrigerators, like many large electrical devices, make a variety of noises during the course of their operation. Some of these can be particularly annoying, including when a refrigerator makes a high-pitched sound that only certain members of the family will hear. Although in many cases this sound will be the result of normal working, there are some steps that can be taken to reduce it or even eliminate it entirely; although in many cases it will be an unavoidable consequence of the unit's operation.
Refrigerators need a solid footing in order to function quietly. If the refrigerator is not balanced correctly, it will vibrate while the motor and compressor are in operation. These vibrations can generate a harmonic in fixtures and other objects around the unit, causing a high-pitched sound. This resonance can be solved either by adjusting the feet on the refrigerator to seat it correctly, or moving the objects the refrigerator is vibrating.
The motor in a refrigerator contains moving parts that spin at a high speed. As the motor spins, it emits a high-pitched sound that is only audible to the upper register of hearing; making it audible to children and some adults with good hearing. This is due to the frequency at which the motor vibrates, generating high-frequency sound waves. The sound is similar to that of computer cooling fans and power supply units.
The compressor is part of the technology used to keep a refrigerator cold. It compresses the coolant before pushing it into the expansion chamber and thus enables the refrigerator to remove heat from the air inside the main body of the unit. This generates heat and causes expansion in the material of the compressor when it is working. As the compressor warms and cools, it will sometimes emit a high-pitched sound.
Refrigerators are not inherently silent devices. When a refrigerator is working, it will produce some noise as a by-product. This is inevitable and should not be considered a defect in the product. However, if the refrigerator makes a high-pitched sound that is too unbearable and all attempts to resolve the issue, such as seating the unit solidly, have been attempted, consider contacting the manufacturer to discuss the problem. They may be able to offer advice.