When we think about what metal is the main one in a refrigerator, we are usually not talking about the external gloss, but about the internal “anatomy” of the device, hidden from the user’s eyes. It is the materials from which the heat exchangers and circuits are made that determine the durability of the unit and its ability to maintain cold for years without serious breakdowns. Different manufacturers use different alloys, and understanding these differences will help you avoid buying a model that is prone to rapid failure.
The internal structure of a modern household refrigerator is a complex engineering compromise between heat transfer efficiency, production cost and corrosion resistance. Aluminium, stainless steel and in rare cases copper these are the three pillars of which The entire refrigeration industry is holding on. Each of these materials has its own unique physical and chemical properties, which directly affect how long your Indesit, LG or Atlant.
Understanding what kind of metal is used in a specific node, allows you to predict possible problems. For example, knowing that the evaporator is made of thin aluminum dictates special care when defrosting so as not to pierce the wall with a sharp object. Let's take a closer look at where and what metals are used, and why engineers choose them.
External casing: steel and its coatings
The most noticeable metal in a refrigerator is the material of its body. In the vast majority of cases, manufacturers use sheet cold-rolled steel. This choice is driven by the need to ensure structural rigidity, protect internal components from mechanical damage, and create a smooth surface for applying decorative coatings. Steel holds its shape well and can withstand the weight of hanging shelves and a compressor.
However, bare steel is susceptible to rust, so it is always coated with a layer of powdered enamel or polymer. More expensive models, such as Bosch Serie 8 or Siemens IQ-700, can use a real stainless steel. This gives the unit a premium look and increased scratch resistance, although it requires special care to remove fingerprints.
⚠️ Attention: Never use abrasive sponges or harsh chemicals to clean the steel case. Damage to the protective polymer layer will lead to the rapid appearance of corrosion, which cannot be eliminated without completely repainting the part.
The thickness of the body metal also plays a role in sound insulation. Heavier and thicker steel sheets better dampen vibrations transmitted from a running compressor. Cheap models often have thin walls that can resonate, creating an unpleasant hum. Therefore, when choosing, pay attention not only to the brand, but also to the weight of the device - a massive body often indicates the use of high-quality materials.
Evaporator: the heart of cold and metal
The evaporator is the very unit where the most important thing happens: boiling the refrigerant and absorbing heat from the chamber. This is where the question most often arises: “which metal in the refrigerator is most susceptible to corrosion?” Historically, Soviet refrigerators and many modern budget models (for example, Biryusa or old ones Atlant) used aluminum. This metal has excellent thermal conductivity and is easy to process, but it has one drawback - it is afraid of corrosion and mechanical damage.
The aluminum evaporator is often called “crying”, since moisture condenses on its surface. Over time, especially in conditions of high humidity and the presence of impurities in the air, aluminum becomes thinner. A leak in this place means the end of the life of the refrigerator, since such thin-walled tubes are practically irreparable. In more modern and expensive models, manufacturers have switched to using anti-corrosion coating or even galvanized steel. They use a tube-fin design, where the tubes are often made of aluminum or steel and the fins are made of thin aluminum foil. This combination allows you to maximize the heat transfer area with minimal weight. However, if the system galvanized steel with anti-corrosion coating or even stainless steel.
In systems No Frost The evaporator design is different. They use a tube-fin design, where the tubes are often made of aluminum or steel and the fins are made of thin aluminum foil. This combination allows you to maximize the heat transfer area with minimal weight. However, if the system No Frost uses an aluminum circuit, the risk of refrigerant leakage due to corrosion still remains, although to a lesser extent than in drip systems.
Condenser and piping: copper versus aluminum
If you look at the back wall of the refrigerator (where there is no protective grille), you can see the coil - this is the condenser where the hot refrigerant releases heat into the room. Here the choice of metal depends on the price segment. Ideally, for maximum efficiency and reliability you need copper. Copper tubes have the best thermal conductivity and ductility, they do not rust (although they can oxidize) and last for decades.
However, copper is an expensive material. Therefore, the mass market (Samsung, LG, Haier budget series) has been using aluminum or steel with copper plating for many years. An aluminum capacitor is lighter and cheaper, but it is more sensitive to vibrations and temperature changes, which can lead to microcracks over time. Steel pipelines are stronger, but conduct heat less well, which makes the compressor work harder.
The connection of different metals in one circuit (for example, a copper compressor and aluminum tubes) requires the use of special adapters, since direct welding of aluminum and copper is impossible. These joints are potential risk points where galvanic corrosion or vibration leakage may occur. This is why the quality of assembly and soldering at the manufacturing plant is critically important.
Why is copper better than aluminum in refrigerators?
Copper has a thermal conductivity of about 400 W/(m K), while for aluminum this figure is about 200-230 W/(m K). This means that the copper condenser transfers heat almost twice as efficiently, allowing the compressor to turn on less often and make less noise. In addition, copper is more ductile and tolerates vibrations better.
Comparative table of heat exchanger materials
To systematize information about what metal in the refrigerator is used for different components, consider a comparative table. It will help you understand the advantages and disadvantages of each material in the context of operation.
| Material | Thermal conductivity | Corrosion resistance | Cost | Where used |
|---|---|---|---|---|
| Copper | Very high | High | High | Premium models, compressors |
| Aluminum | Medium/High | Low (afraid of acids/alkalis) | Low | Evaporators, budget condensers |
| Stainless. steel | Low | Very high | Medium/High | Housing, internal chambers |
| Galvanized steel | Low | Medium (depending on the zinc layer) | Low | Pipelines, rear wall |
The table shows that ideal material does not exist. Engineers are forced to balance between price and quality. For example, using stainless steel for the evaporator would be ideal in terms of durability, but its thermal conductivity is too low for effective cooling, and the cost would make the refrigerator unaffordable for most buyers.
Internal chamber: plastic or metal?
When asking the question “what metal is in the refrigerator,” many users mean the material of the internal shelves and walls of the chamber. Here in 95% of cases you will find ABS plastic. It is impact-resistant, food-safe material that is easy to clean and does not absorb odors. Metal internal chambers are extremely rare, mainly in professional catering equipment or in very old Soviet models.
However, metal elements are still present inside. These are shelf guides that are often made of chrome-plated steel or durable plastic with a metal core. In some models Gorenje or Electrolux you can find glass shelves with aluminum edging, which gives them strength and an aesthetic appearance. The back wall inside the chamber, where the channel for air circulation in the systems is located No Frost, is also made of plastic.
Why not metal inside? The metal chamber would quickly become covered with frost, would be slippery for food (glass jars would break) and would create a “cold bridge”, increasing energy consumption. Plastic is an excellent heat insulator, helping to keep the cold inside and not let heat in from the outside.
☑️ How to determine the evaporator material when purchasing
Compressor: metal motor
The heart of the refrigerator - the compressor - also consists of metals. The compressor housing is usually made of steelpainted black. Inside are the copper windings of the motor and the steel plates of the valve mechanism. The quality of the metal and the precision of processing of these parts determine how quiet and long the motor will operate.
Modern inverter compressors, which can be found in models LG Linear or Samsung Digital Inverter, have a more complex design, but the basic materials remain the same. The only difference is in the control technology and motor suspension, which reduces vibration. During operation, the steel housing of the compressor can heat up to 60-80 degrees Celsius, which is normal thermal conditions.
⚠️ Attention: If you plan to transport the refrigerator, remember that the compressor is suspended on springs inside the steel housing. If it shakes, it can damage the pipelines. Always secure the compressor with shipping bolts before moving, if the design of the model provides for this.
Problems and corrosion: the enemies of metal
The main enemy of the metal parts of the refrigerator is not time, but moisture in combination with aggressive environments. If you spill acid (lemon juice, vinegar) or alkali on an aluminum evaporator or shelves and do not wipe them off, the corrosion process begins. In places where the protective layer is damaged, characteristic white or red spots appear, which over time turn into through holes.
Another factor is electrochemical corrosion. It occurs when different metals (copper and aluminum) are present in the system and there is even a microscopic amount of moisture with dissolved salts. This is why it is so important to monitor the integrity of the drainage system. If water from the evaporator tray stagnates and comes into contact with metal elements, the service life of the unit is sharply reduced.
To extend the life of metal elements, it is recommended:
- 🧼 Regularly wash the internal surfaces with mild products without abrasives.
- 💧 Make sure that the products do not touch the back wall (it’s cold there and there may be moisture).
- 🔍 Periodically inspect the seals and drainage hole for blockages.
Frequently asked questions about refrigerator materials
Is it possible to paint a rusty refrigerator body?
Yes, it is possible. It is necessary to strip the rust down to the metal, degrease the surface, coat it with a rust primer (converter) and then apply a special enamel for household appliances. However, if the rust is through, you will first need to weld or solder the hole.
What is the difference between a refrigerator with a steel evaporator and an aluminum one?
A steel evaporator (often galvanized) is much stronger and is not afraid of accidental blows with a knife during defrosting. Aluminum is lighter and cheaper, but requires extremely careful handling. Visually, steel is darker and more matte, aluminum is lighter and shiny.
Why is there sometimes a metallic smell inside the refrigerator?
This may indicate that corrosion of metal parts has begun or that you are storing foods with a strong smell in an open metal container. Also, the smell can come from new equipment (it disappears in a couple of weeks) or from problems with wiring, if the smell resembles burnt metal.
Is aluminum in the refrigerator harmful for food?
No, it is not harmful. The aluminum in the evaporator design does not come into direct contact with the products; it is hidden behind a plastic wall or located in a separate sealed circuit. Even in older models with an open evaporator, the contact of food with metal is minimal and does not pose a threat to health.
Which metal conducts cold better?
Silver conducts heat (and cold) best, but it is not used in technology because of the price. Among the most common materials, the leader is copper, followed by aluminum. Steel conducts heat much worse, so for heat exchangers it is used less often or the surface area is increased.