Mini fridges are classified into three categories: compressor, thermoelectric, and absorption. An absorption refrigerator doesn’t make much noise, while most thermoelectric and compressor mini fridges are unpleasantly loud. So you may wonder why mini fridges are so loud.
Mini fridges are so loud because of their specific technology. Thermoelectric mini fridges are loud because the fan runs constantly, while compressor mini fridges are loud due to the mechanical functions, excess vibration, loose parts, and noisy evaporator fan.
Usually, thermoelectric and compressor mini fridges are loud, though some models are significantly quieter. The loudness and nature of the sounds depend on the condition of the mini fridge. Keep reading to understand all the factors that make mini fridges so loud.
7 Reasons Why Mini Fridges Are So Loud
Standard or full-size residential refrigerators don’t operate silently. You can hear a mild buzzing or humming noise from the compressor. Also, regular fridges make clicks and other sounds as the compressor cycles on and off, the defrost mode kicks in, and the water circulates in the unit.
Therefore, mini fridges (or smaller versions of the standard refrigerator and freezer using the same cooling components) won’t be completely quiet. The sole exception is the type of mini fridges that use absorption technology.
That said, most compressor mini fridges tend to be much louder than their full-size counterparts. Further, the thermoelectric mini fridges use a completely different technology known as the Peltier effect. So, the reason for a Peltier mini fridge being loud is different from those using compressors.
1. The Cooling Fan in Thermoelectric Mini Fridges Is Loud
Remember how millions of people tuned in to watch the world premiere of the Xbox Mini Fridge? Gamers the world over hoped they wouldn’t have to get up from their console to fetch a cool drink ever again. Unfortunately, that convenience comes at a price — a constant loud noise.
The Xbox Mini Fridge, like other such thermoelectric cooling appliances, uses a Peltier module. This mini fridge doesn’t have a refrigerant, compressor, condenser, evaporator, etc. Instead, a module comprising two distinct conductors cools the fridge and transfers heat away.
Here are the main components of a thermoelectric mini fridge:
- Peltier module
- Heat sink
- Cooling fan
- Control board
- Power switch
- LED lights
For the purposes of this article, I’ll highlight the Peltier module, heat sink, and cooling fan. But first, let me explain how the Peltier effect works so you can easily understand why the fan needs to operate all the time.
How a Thermoelectric Mini Fridge Using a Peltier Module Works
A Peltier module is a chip-like plate. The two sides of this plate are conductors that change temperature when connected to a power source. Every thermoelectric plate or Peltier module has a rated voltage and amperage. Thus, when you provide the required power, the electric current changes the temperatures of the two conductors on the plate.
One side of the plate gets hotter, and the other conductor surface gets colder. This phenomenon is the Peltier effect. Naturally, the colder plate is inside the mini fridge that cools your goodies. And the hotter side facing outward is assembled with a heat sink.
The cooling fan is installed on the heat sink. This installation is exactly how a processor fan is set on the chipset and its heat sink in your desktop computer. The sole difference is that the one on a thermoelectric mini fridge is much bigger than the processor fan.
A thermoelectric or Peltier mini fridge’s cooling fan has a similar size and capacity as the standard models you’re probably familiar with in an SMPS. Basically, this fan is no different from those you use to cool your PCs and other small- to medium-sized electronic appliances.
This cooling fan is connected to the same circuit as the Peltier module. Thus, when you turn on a thermoelectric mini fridge, you are powering the Peltier module as well as the fan. This fan needs to run all the time to cool the heat sink. Otherwise, your thermoelectric mini fridge won’t work.
Now, the fan on your computer processor’s heat sink is quieter than those cooling the cabinet and the SMPS. These typical cooling fans also work harder as they deal with a hotter heat sink. You can expect a similar experience with a cooling fan on a Peltier mini fridge.
Therefore, a thermoelectric mini fridge is continuously loud unless you have a super-efficient fan that operates without making any audible sound.
Furthermore, like all fans, the one cooling your Peltier mini fridge will wear out and become inefficient over time. Also, the heat sink usually gets dusty. These factors will progressively worsen the noise. So, a thermoelectric mini fridge with a cooling fan behind it may get louder as it ages.
2. A Mini Fridge Compressor Makes Constant Noise
All fridge compressors make some noise when they operate. This mellow but steady humming or buzzing sound is inevitable because a refrigerator compressor has several moving parts inside. So, your mini fridge compressor doesn’t and won’t operate silently.
Also, a compressor circulates the refrigerant from the evaporator through its suction tube and out of the discharge port to the condenser coil. Therefore, a typical mini fridge compressor isn’t only a pressurizing device but also a pump, making the humming or buzzing unavoidable.
Now, several issues can make a mini fridge compressor louder than the one on your standard refrigerator and freezer. Here are a few common reasons or factors:
- A home office, games room, bedroom, and other spaces smaller than the living or dining area have less ambient noise.
- The compressor’s sound sounds louder because you’re likely to be closer to your mini fridge than a full-size refrigerator.
- The small compressor in a mini fridge keeps working continuously, consistently producing the buzzing or humming sound.
- The compressor is overworked due to inefficient cooling and heat loss through the condenser coil in a mini fridge.
A Mini Fridge Compressor May Run Longer and Work Harder
A mini fridge naturally has a smaller compressor, which has to work much harder than a medium or larger variant on a standard refrigerator. For example, an 1/8 HP (93.21 W) compressor rated for 115 W (0.15 HP) has a lot less power than one with 1/2 HP (372.85 W) capacity running on 400 W (0.54 HP).
In effect, your mini fridge compressor may run all the time to sustain the temperature or mode you set on the thermostat. A constantly running compressor will be stressed, and it might fail eventually. You’ll also hear the noise continuously if the compressor doesn’t cycle off.
This problem gets compounded when you factor in a common design aspect of mini fridges that have compressors: Many of them don’t have a condenser fan. Instead, such units have the condenser coil aligned around the insulation inside the housing.
Thus, the condenser coil has no fan to facilitate an efficient and effective heat transfer. Plus, the coil essentially transfers heat from the warm refrigerant to the mini fridge’s housing. This issue is why the mini fridge’s housing feels hot to the touch.
On the other hand, all standard refrigerators have a condenser coil and fan, usually located at the base. The fan also cools the compressor and prevents it from overheating.
How efficient a condenser coil is at transferring heat to a mini fridge housing depends on the model, design, material, etc. But the laws of physics and thermodynamics mean that fan-regulated and increased cool airflow facilitate better heat loss from a condenser coil.
Thus, your mini fridge compressor will work longer and harder to compensate for the inefficient heat loss from the condenser coil. Also, the relatively warmer refrigerant in the evaporator won’t extract as much heat from inside the mini fridge as it would if it was cooler.
Therefore, the mini fridge compressor may continue to run and make the noise constantly as long as it operates. This noise will subside only when the compressor cycles off. If a compressor is overworked, it will have failing parts, which can worsen the noise problem.
3. Some Parts Have Unusual or Excessive Vibration
Mini fridge compressors vibrate when they operate, and this process will generate some resonance. Also, the parts connected to the compressor may vibrate as a result. For example, the evaporator and condenser coils connected to the compressor may vibrate.
A normal vibration shouldn’t create a loud or unpleasant noise. However, you may hear loud noises if there’s unusual vibration. For instance, the mini fridge compressor has several internal components that are suspended on a few springs at the base of the housing.
The outer case of a mini fridge compressor is usually steel (forged, cast, or alloy). Inside the case or housing, a compressor’s motor, piston, valves, and everything else combines to make a self-contained unit. This unit rests on springs, so there’s an inevitable vibration that also contributes to the noise.
The noise may be louder if the vibration is unusual or excessive. Any unusual vibration can affect the other connected parts. Therefore, you may hear a mini fridge making louder noises than you’d expect.
4. Any Loose Components Can Make Unusual Sounds
Like vibration, loose components can make strange noises. A mini fridge has many screws, nuts, and retainers in different parts. If these fittings are loose, you may hear a clicking, clanking, or other strange sounds. However, a brand new mini fridge shouldn’t have loose components.
This problem isn’t unique to mini fridges. Standard refrigerators can also make louder noises with some loose components. Luckily, you can readily fix this issue by tightening any loose nut, screw, retaining clip, etc.
The simplest way to detect a loose component is by observing the noise and finding its source. If the sound’s origin is behind the mini fridge, check the fittings around the compressor. If the sound comes from inside, check the racks and anything else in the fridge.
5. Mini Fridges With Freezers May Have Frost Buildup
Many mini fridges have a freezer. Generally, the evaporator coil and fan vents are in the freezer section. If the freezer has frost or ice buildup, a mini fridge may be louder than usual. Regular or full-size refrigerators with freezers have an automatic defrost feature, hoses, and a drain pan. Most mini fridges lack such features.
So, your mini fridge won’t defrost unless you turn it off and allow the ice to melt. The ice buildup can also cause problems, however.
One likely issue is airflow. The evaporator fan behind the vents in the freezer won’t circulate the air as freely as it would without the ice buildup.
Thus, you may hear a weird and loud noise. Ice in the freezer doesn’t necessarily mean the mini fridge is cold and the compressor should shut. In fact, frost can act as an insulator because the lack of airflow won’t cool the rest of the fridge.
Also, excessive frost in a mini fridge loaded with your food and drinks can worsen the vibration that already causes some noise. If there’s any frost buildup in the vents or on the evaporator fan, you may hear a rattling or similar noise.
6. The Evaporator Fan Can Be Noisy in Some Cases
The evaporator fan is inside the mini fridge, so you shouldn’t hear a loud sound unless you open the door. However, an evaporator fan may be icy, stuck, or failing. The fan’s blades may also strike the interior case or freezer panel of the mini fridge. Thus, you may hear a strange loud noise.
Like a typical condenser fan, the one serving the mini fridge’s evaporator coil and internal vents can be loud. Broken or misaligned blades can strike against the parts around the fan. You may also have a failing motor that can produce a loud noise.
7. Mini Fridge Placement, Leveling, and Alignment Issues
Last but not least is how you position a mini fridge. If it’s level, you shouldn’t hear any annoying sounds. Otherwise, any alignment issues can cause or exacerbate the loud noises. Let’s say you place a thermoelectric mini fridge against the wall that reflects and amplifies the fan’s noise. Or, you have an unleveled or misaligned compressor mini fridge. Such installations can worsen the loud noises, vibrations, resonance, etc.
Also, if your mini fridge has a defrost feature, an unleveled or misaligned drain pan can make some noise as it vibrates.
While most mini fridges are loud, you can shop for the quietest ones. Avoid a thermoelectric mini fridge if you don’t want a cooler fan to run all the time. If you already have a Peltier mini fridge, consider replacing a loud fan with a new, quieter one.
For compressor mini fridges, check if the appliance is leveled, tighten the components if any are loose, and consider keeping the unit in a soundproofed cabinet. Also, make sure your mini fridge doesn’t frost.