Why Is My Fridge Making a Humming Noise?
A steady, low hum from a fridge is normal. It is the compressor running. What matters is how that hum sounds: steady and quiet is fine, loud or continuous may mean the fridge is working harder than it should, and new sounds like clicking, rattling, or grinding are worth investigating. The sound type and pattern tells you most of what you need to know.
Identifying the sound
Fridges make several distinct types of noise during normal operation. The table below covers the most common, what causes each one, and whether it is worth investigating.
The compressor pumps refrigerant around the cooling circuit to maintain temperature. It cycles on and off throughout the day. When running it produces a steady low hum, the most common sound a fridge makes. Normal compressor noise is around 35 to 45 dB: audible in a quiet room, not intrusive during normal activity.
A gurgling or liquid-moving sound, particularly after the compressor switches off, is the refrigerant settling through the pipes. Completely normal and more noticeable in quieter environments or with newer fridges. No action needed.
The plastic interior panels expand and contract as temperature cycles inside the fridge. This produces occasional cracking sounds, more noticeable when the compressor first starts or stops. Normal and not a fault.
If the hum has noticeably increased in volume, the compressor is likely running more continuously than normal. The most common causes are poor ventilation, a dirty condenser coil reducing heat dissipation, or the thermostat set lower than needed. A fridge that never seems to switch off is showing this pattern.
Rattling when the compressor runs usually means the fridge is vibrating against something: a wall, adjacent cabinet, or an uneven floor. Check that the fridge stands level (most have adjustable feet), that there is a small gap between the unit and any adjacent surface, and that no bottles on top are vibrating sympathetically.
A loud click followed by a brief buzz then silence, repeated every few minutes, suggests the compressor is trying to start but failing. This often points to a faulty start relay. If the fridge also feels warmer than usual, contact an engineer before continued use.
Grinding from inside the fridge or freezer usually comes from the evaporator fan. Ice build-up on the blade, debris caught in the airflow, or failing fan bearings can all cause this. Check the freezer for ice accumulation around the fan housing. If defrosting does not resolve it, the fan motor needs professional inspection.
Why a continuously running fridge is worth addressing
A fridge compressor is designed to cycle on and off throughout the day, maintaining temperature rather than running continuously. When it runs almost without stopping, it is working harder than it needs to, which increases energy consumption noticeably and puts additional wear on the compressor over time.
The most common reasons a fridge runs continuously are poor rear ventilation (too close to the wall or enclosed in cabinetry without adequate airflow), a dirty condenser coil at the back of the appliance that cannot dissipate heat efficiently, a door seal that has lost its compression and lets warm air enter, or a thermostat set colder than the room temperature requires. All of these are worth checking before assuming a compressor fault.
A fridge running continuously uses considerably more energy than one cycling normally. For more on how fridge running costs add up and what reduces them, the kitchen appliance running costs guide covers condenser cleaning, door seal checks, and thermostat settings in the fridge and freezer section.
Things to check before calling an engineer
- Confirm the fridge has at least 5cm clearance at the rear and sides for ventilation
- Check the fridge is level using the adjustable feet (a slight forward tilt helps the door self-close)
- Ensure the fridge is not touching adjacent cabinets, walls, or other appliances
- Vacuum or brush the condenser coils at the back or base of the appliance to clear dust accumulation
- Check the door seal by closing the door on a piece of paper. If it pulls out easily, the seal needs replacing
- Check the freezer compartment for ice build-up around the rear panel or fan housing
- Confirm the thermostat is not set colder than needed (3 to 5°C for the fridge, -18°C for the freezer)
- If the fridge is making loud clicking at startup and feels warmer than usual, call an engineer
For CATA fridge and fridge-freezer models, manuals, and service contacts, visit the product support pages. Browse the CATA cooling range for current fridge and fridge-freezer models. For energy-saving habits across all kitchen appliances including fridges, see the kitchen appliance running costs guide.
Common questions answered
Is it normal for a fridge to hum all the time?
A fridge that hums almost continuously without switching off is working harder than it should. Normal operation involves the compressor cycling on for a period, then switching off as the target temperature is reached. If the compressor never seems to stop, check ventilation clearance, condenser coil cleanliness, door seal compression, and thermostat setting before assuming a fault.
My new fridge is louder than my old one. Is that normal?
Possibly. Modern fridges with more efficient inverter compressors can sound different from older single-speed compressors — sometimes more variable in pitch as the speed adjusts. A new fridge also tends to run more frequently in the first 24 hours as it cools down from room temperature to operating temperature for the first time. If the noise persists at the same level after 48 hours, check the installation clearances and level.
How often should the condenser coils be cleaned?
Once a year is sufficient for most households. More often if you have pets that shed hair, as this accumulates on condenser coils particularly quickly. The coils are usually at the back of the fridge or accessible behind a panel at the base. Use a vacuum cleaner with a brush attachment or a long-handled brush. It takes under five minutes and can noticeably reduce running noise and energy consumption.
The fridge makes a sound when it is first plugged in. Is that normal?
Yes. When a fridge is first switched on from room temperature, the compressor runs continuously for an extended period as the interior cools from ambient to target temperature. This can take two to four hours, during which the hum is louder and more constant than it will be in normal day-to-day operation. This is entirely normal and resolves once the fridge reaches its set temperature.
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