Extraneous sounds coming from the kitchen often become a source of irritation, especially at night or in studio apartments. Humming, clicking or gurgling can indicate both normal operation refrigerantand incipient malfunctions of the unit. Understanding how to correctly measure noise levels helps determine whether a device is within acceptable standards or requires professional intervention.
Modern household appliances are classified by sound pressure level, and deviation from the values claimed by the manufacturer is an alarming signal. Many owners confuse the operating hum of the motor with vibration of the housing caused by improper installation. Decibelometer allows you to separate the norm from the pathology, but to obtain objective data it is necessary to follow a strict measurement protocol in silence.
In this article we will analyze the technical nuances of acoustic measurements, consider the permissible volume limits for different classes of equipment and find out which sounds are considered critical. You will learn to distinguish between the aerodynamic noise of a fan and the mechanical knock of a compressor, which will save time during diagnostics.
Noise level standards for household appliances
The sound pressure level is measured in decibels (dB), and the A scale, designated as dBA, is used to assess the perception of the human ear. According to current standards, modern refrigerators are considered quiet if their indicator does not exceed 40 dBA. Models with noise levels up to 36 dBA belong to the premium class and are often equipped with inverter compressors.
It is worth considering that the values stated in the passport were obtained in ideal laboratory conditions, where there is no extraneous noise and vibration. In actual operation, the figures may be higher due to resonating surfaces or proximity to walls. European standards require mandatory indication of acoustic characteristics on the energy efficient label, which allows you to compare models before purchasing.
⚠️ Attention: If the measured noise level exceeds the passport data by more than 10 dB, this may indicate generation bearing life or engine shaft misalignment.
Differences in volume often depend on the type of refrigerant used and the design of the compressor group. Older models with linear compressors operate louder, creating a characteristic hum when starting and stopping. New control systems (inverter) operate more smoothly, avoiding sudden changes in sound pressure.
Necessary tools for accurate measurements
To carry out professional diagnostics of the acoustic background, it is not enough to rely on the subjective perception of hearing. The main tool is sound meter (decibel meter), which can be purchased as a separate device or use a specialized smartphone application with a calibrated microphone. The accuracy of household meters is usually ±1.5 dB, which is quite enough for home diagnostics.
In addition to the measuring device, you will need a stopwatch to record the duration of operating cycles and a notepad to record readings at different time intervals. It is important to exclude background noise: a running TV, conversations or street noise can distort the measurement results. Before starting the procedure, it is recommended to close the windows and turn off other household appliances.
If you are using a smartphone, make sure that the microphone is not covered with a case or contaminated with dust. There are applications that allow you to calibrate a microphone against a reference sound, which increases the reliability of the data. Professional audio analyzers also allow you to see the frequency spectrum, helping to determine the source of the sound (low-frequency hum or high-frequency whistle).
Step-by-step instructions: how to correctly measure decibels
The measurement process must be carried out in several stages in order to obtain an average and objective value. First, the refrigerator must operate normally for at least 24 hours after installation or defrosting. Measurements are taken at a distance of 1 meter from the front panel of the device and at a height of 1.5 meters from the floor, which corresponds to the level of the ears of a standing person.
Record the readings while the compressor is operating, ignoring moments of idle time. If the device is equipped with a No Frostsystem, wait until the fan turns on and write down a separate value for this mode. Repeat the procedure three times with an interval of 15 minutes to eliminate accidental power surges or temporary water hammer in the system.
☑️ Checklist for preparing for measurements
The results are recorded in a table for comparison with passport data. If the indicators differ greatly on different days, perhaps the problem lies in unstable voltage in the network or overheating of the motor due to poor ventilation. The critical threshold is considered to be a value above 55 dB, in which a long stay in the kitchen becomes uncomfortable for a person.
| Operating mode | Norm (dBA) | Permissible limit (dBA) | Probable cause of excess |
|---|---|---|---|
| Idling (compressor) | 34–38 | 42 | Wear of bearings, tube vibration |
| Fan operation | 36–40 | 45 | Blade contamination, imbalance |
| Freon circulation | 30–35 | 40 | Airing of the system, capillary bend |
| Start/stop | to 50 (short-term) | 55 | Malfunction of the starting relay |
Analysis of characteristic sounds and their sources
Different types of sounds indicate specific components that require attention. A monotonous low-frequency hum is most often produced by itself compressor, especially if it is attached to shock absorbers that have lost elasticity. The ringing of metal shavings or grinding indicates mechanical destruction of the internal parts of the motor.
Gurgling and overflowing of liquid is the sound of moving through the pipes refrigerant. Under normal conditions, these sounds are quiet and can only be heard when the ear is directly applied to the back wall. If the gurgling is loud and accompanied by vibration of the housing, there may be a freon leak or an air lock in the system.
Whistling sounds are usually produced by air passing through the channels of the No Frost system. If the whistling gets worse, check that the air filters are clean and there are no ice plugs in the drainage. Sharp clicks when turning on or off are normal for thermostats and start relays, but frequent repetitions may indicate their malfunction.
Why does the refrigerator hum louder at night?
During the day, background noise masks the operation of the equipment. At night, in silence, the same level of sound pressure (for example, 40 dB) is perceived by a person as louder due to the contrast with the surrounding silence and the psychoacoustic characteristics of hearing.
Factors that increase noise and vibration
Often the cause of increased noise is not a breakdown, but improper operation or installation. First of all, check the horizontal installation: if the refrigerator is on an uneven floor, vibration from the running motor is transmitted to the body and floor, creating resonance. Adjusting the support legs helps eliminate this effect.
The gap between the back of the device and the wall should be at least 5–7 cm for free air circulation. If there is insufficient clearance, the motor overheats, working under increased load and producing louder sounds. Also make sure that the internal shelves and dishes inside do not touch each other, creating rattling.
⚠️ Attention: Never place the refrigerator close to the wall or in a niche without gaps - this will cause the condenser to overheat and increase the noise level by 5-10 dB.
Vibration can be transmitted from other sources, for example, from a washing machine operating in the next room if they are connected to common communications. In rare cases, the cause of humming is unstable voltage in the network, causing the electric motor to operate in abnormal mode.
Methods for reducing noise levels without repair
If measurements show a slight excess of the norm, you can try to reduce the noise level yourself. An effective way is to install the refrigerator on a special one vibration-isolating substrate made of dense rubber or cork. This breaks the path of transmission of mechanical vibrations from the compressor to the floor.
Check the tightness of all visible bolts and fasteners, especially those that hold the compressor casing and condenser. Over time, constant vibration weakens the connections and parts begin to rattle. For pipe lines, you can use special damper clamps or gaskets made of soft material.
If the noise is caused by the operation of the fan, it can be removed and the bearing or axle lubricated with special oil for household appliances. Dust on the blades also creates imbalance and noise, so regular cleaning of the inside of the freezer from ice and dirt is mandatory.
When you need to call a professional
There are situations when independent measures will not help and the intervention of a professional is required. If, after adjusting the legs and checking the internal shelves, the operating volume has not decreased and the measured values exceed 50 dB, the compressor itself is likely worn out. Replacing this unit is a complex procedure that requires evacuation of the system and refilling with freon.
A constant loud knock, similar to metal hitting metal, often indicates that the engine piston group is out of order. Operating such a refrigerator is dangerous: the motor may jam, which will lead to a short circuit or fire in the wiring. Also, the help of a technician is needed when a refrigerant leak is detected, which can be suspected by a whistle and lack of cooling.
⚠️ Attention: Attempts to independently disassemble a sealed circuit or compressor without special equipment and a license are prohibited by the legislation of many countries due to environmental risks.
The specialist will conduct diagnostics using professional equipment that more accurately determines the source of sound and pressure in the system. In some cases, it is cheaper and more expedient to replace an old, noisy refrigerator with a new model with an inverter compressor than to repair an outdated unit.
Is it possible to soundproof the outside of a refrigerator?
It is absolutely forbidden to glue the external walls of the refrigerator with soundproofing materials. This will disrupt heat exchange, lead to overheating of the motor and increased energy consumption.
Is it normal if the refrigerator makes sounds every 15-20 minutes?
Yes, this is normal operation for most models. Cycling the compressor on and off (or changing its power in inverter models) is necessary to maintain the set temperature. The interval depends on the load of the chambers, the ambient temperature and the tightness of the doors.
Why is a new refrigerator noisier than the old one?
Modern models often use more powerful compressors and active air circulation systems (No Frost, Multi-Airflow), which create aerodynamic noise. Older refrigerators may have been quieter when idle, but ran less frequently and less efficiently, and their insulation may have degraded over time, masking the real noise.
How can you tell the difference between compressor noise and fan noise?
A compressor produces a low-frequency hum and vibration that can be felt by the cabinet. The fan produces a higher-pitched, whistling or rustling sound that may change when the door is opened (the fan turns off on some models). Sound localization also helps: the motor is located at the bottom at the back, and the fan is inside the freezer or refrigerator compartment.
Does the amount of food affect the noise level?
Yes, a fully loaded refrigerator is quieter. The products act as additional sound insulation and an acoustic buffer by absorbing vibrations. Empty shelves and walls can resonate, increasing the sound of the unit.