Starting a refrigerator is not just turning on the compressor, but a complex physical process, accompanied by a sharp jump in energy consumption. Many owners of household appliances notice that when the unit is turned on, the light in the room may become dimmer for a split second, or the voltage regulator may make a characteristic click. This is direct evidence that at the moment of start-up the device consumes energy several times more intensely than in normal operation.
Understanding this how many kilowatts does a refrigerator consume when starting upis critical for the correct selection of a generator, stabilizer or UPS. An erroneous calculation of power often leads to the fact that the protective automation is triggered and the equipment cannot start. In this article we will analyze in detail the nature of starting currents, their effect on wiring and ways to minimize the load on the electrical network.
The energy expended in the first seconds is not wasted, it is necessary to overcome inertia and create initial pressure in the system. However, it is this short-term peak that creates the maximum load on the socket contacts and wiring, which must be taken into account when installing new power supply lines for the kitchen.
The nature of the starting current in the compressor
The main consumer of energy in the refrigerator is the compressor, which is an electric motor. When voltage is applied to the motor windings, the rotor is still motionless and the winding resistance is minimal. This is why it occurs starting current, which can exceed the nominal operating values by 3–7 times. This process lasts a fraction of a second, but it is precisely this that determines the requirements for the power source.
The physics of the process is such that significant force is required to spin up the engine shaft and create the initial coolant pressure. If there is residual pressure left in the system, the load on the engine increases many times over. Modern models with inverter compressors Liebherr or LG solve this problem through a soft start, but classic linear models are still widespread.
⚠️ Attention: Frequent switching on and off of the refrigerator due to surges in the starting current can lead to overheating of the motor windings and compressor failure ahead of schedule.
It is important to distinguish between active and reactive power at this moment. Although the meter mainly takes into account the active component, the total power at the moment of start is high. This creates a load on the wires, which may not be visible visually, but leads to heating of the connections.
The difference between starting and operating power
The operating power of the refrigerator indicated in the passport is usually 100–200 W. However, the figures showing how many kW does the refrigerator consume at startup?can reach 1–1.5 kW and even higher for powerful models. This difference is due to the need to overcome static friction and inertia of mechanical parts at rest.
Consider an example: if the nameplate indicates a consumption of 150 W, then the starting current can be about 600–900 W in terms of active power, taking into account the power factor. For inverter systems, this gap is much smaller, since the engine speed is controlled electronically, excluding sudden jumps.
Below is a table showing the approximate power ratio for different types of compressors:
| Compressor type | Operating power (W) | Starting power (W) | Excess factor |
|---|---|---|---|
| Linear (old model) | 140–180 | 800–1000 | 5–6 times |
| Linear (modern) | 100–150 | 500–700 | 3–4 times |
| Inverter | 80–120 | 150–200 | 1.5–2 times |
| Two-compressor (in total) | 200–300 | 1200–1500 | 5–6 times |
As can be seen from the data, two-compressor models create the greatest load, especially if both units will try to start at the same time. The electronics of modern refrigerators Bosch or Electrolux usually space the start of compressors over time to avoid the summation of peak loads.
The influence of the compressor type on energy consumption
The type of installed engine directly dictates the nature of energy consumption. Classic piston compressors operate on an “on-off” principle, which is always accompanied by a high starting current. At the moment of start, the piston must compress the gas, and if the valves are not ideal or there is little freon in the system, the load increases.
Inverter technologies introduced by brands like Samsung i Whirlpoolallow the engine not to stop completely, but only to reduce speed. Thanks to this, the question of how many kilowatts the refrigerator consumes at startup is less relevant for them, since a sharp start simply does not occur. The engine smoothly gains power, consuming a current close to the rated one.
- 🔌 Linear compressors: Characterized by a noisy start-up and high peak consumption, require robust wiring.
- 🌀 Inverter models: Provide a quiet start, low starting current and high energy efficiency class A++.
- ⚙️ Linear inverter: Hybrid version, where the start-up occurs softly, but the piston design is preserved for reliability.
It is worth noting that even in inverter models, when initially turned on after a long time idle time, increased consumption may be observed until the system reaches operating temperature conditions. However, this cannot be compared with the shock loads of older models.
When choosing equipment for a summer house or a place with unstable voltage, you should (prefer) inverter models. They are less sensitive to voltage surges precisely due to the absence of heavy inrush currents, which often cause the protection to trip.
Calculation of the required power of the generator and stabilizer
When selecting equipment for backup power or network protection, you must focus not on operating values, but on starting values. If you buy a 500 W stabilizer for a refrigerator that consumes 150 W in operation, it will most likely go into protection the first time the compressor starts.
The calculation formula is simple: the operating power must be multiplied by the starting current coefficient (usually 3-5) and add a margin of 20%. For example, for a refrigerator with a consumption of 200 W, the calculation would be: 200 W × 5 = 1000 W. Plus 20% of the margin gives us 1200 W. This is exactly the kind of stabilizer or generator that is needed for safe operation.
⚠️ Attention: Gasoline generators often do not tolerate sudden load surges. For refrigerators, it is recommended to use generators with a power reserve or an AVR stabilization system.
Particular attention should be paid to the shape of the output signal. For refrigerators with electronic control and inverter compressors, it is critical pure sine wave. A modified sine wave produced by cheap inverters can lead to overheating of the motor and damage to the control board.
It is also worth considering that at low voltage in the network, the starting current may last longer, since the engine does not have enough power to quickly gain speed. This leads to humming and overheating of the windings. The stabilizer must have a sufficient reaction speed to compensate for the drawdown at the time of start.
☑️ Check before purchasing a stabilizer
Effect of temperature and system condition on startup
External factors significantly influence how much energy is required to start. Ambient temperature plays a key role: in a hot room, the condenser transfers heat less well, the pressure in the system is higher, and it is more difficult for the compressor to start. In winter, on the contrary, starting is easier, but it may take longer to get into operation.
The condition of the refrigerant and the cleanliness of the condenser are also important. If the condenser is clogged with dust, the efficiency of heat transfer decreases and the condensation pressure increases. As a result, at the next start, the compressor will encounter increased resistance of the environment, which will increase the starting current and the time to reach the rated mode.
The presence of defects in the electrical part, such as a faulty starting relay or capacitor (in single-phase motors), can lead to the fact that the engine will hum, but will not start. At this moment, a huge current is consumed, close to the short circuit current, which often ends in the winding burning out.
Why does the refrigerator hum, but does not start?
If you hear a hum, but the compressor does not turn on, the piston may be jammed or the starting relay has failed. At this moment, the current consumption is maximum, and it is necessary to immediately turn off the power to the device to avoid a fire.
Regularly cleaning the rear grille of dust and providing clearance for ventilation helps maintain normal pressure in the system. This indirectly reduces the load on the electrical network when the compressor is turned on.
Practical tips for reducing the load on the network
To minimize the negative impact of inrush currents on the home network, you can use several proven methods. First of all, you should not plug the refrigerator into the same outlet with other powerful consumers, such as a microwave oven or an electric kettle.
The use of a separate wiring line with a cable cross-section of at least 1.5 mm² (preferably 2.5 mm²) for the kitchen area is a safety requirement. Old wiring with aluminum conductors may not withstand repeated starting surges, which will lead to heating of the contacts and melting of the insulation.
- 🔌 Separate socket: Connect the refrigerator directly, without extension cords and tees, which often have poor contact.
- ⏱️ Time relay: For dachas, you can use a turn-on delay relay, to avoid starting immediately after voltage appears in the network.
- 🛡️ Safety automation: Install an RCD and a circuit breaker with characteristic "C", which is intended for devices with high starting currents.
If you notice that The light blinks every time the refrigerator is turned on, this is a signal that the wiring is overloaded. In this case, you need to call an electrician to check the contacts in the panel and sockets.
Frequently asked questions (FAQ)
Can inrush current refrigerator, knock out the machine in the panel?
Yes, if the machine is selected incorrectly. For refrigerators with high starting currents, it is better to use machines with a “C” characteristic (for example, C10 or C16), which can withstand short-term overloads of up to 5–10 ratings. Machines with characteristic "B" may operate falsely.
How many watts does the refrigerator consume in the first hour after turning on?
In the first hour after defrosting or first turning on, consumption will be maximum, since the compressor will work continuously until the temperature rises. If the operating power is 150 W, then in an hour it will consume about 0.15 kWh, not counting starting peaks, which are not as significant for the energy meter as long-term operation.
Do you need a stabilizer for a new inverter refrigerator?
Modern inverter models Samsung, LG often have built-in surge protection and a wide operating range (for example, 100–240 V). However, in networks with critically unstable voltages, an external pure sine wave regulator is still desirable to protect the electronics.
Why does an old refrigerator consume more at startup than a new one?
Over time, mechanical parts wear out, friction increases, and moisture may accumulate in the system or the amount of refrigerant may change. All this increases the load on the engine at the time of start, requiring more energy to spin up the shaft.