A standard-sized chest freezer will generally use 1-1.5 amps during regular use. However, the exact amount of amps that your chest freezer uses at any given time depends on several different factors.
Chest freezers are great to have in your home but you may be wondering how much power they use? When it comes to amps, it’s not always simple. While that’s true, a standard 7 cubic foot freezer will draw around 1.5 amps during regular use.
Appliances like chest freezers have compressor units, which require more power than appliances without compressors in them. You can estimate how much power your freezer needs if you know how many amps it draws from the socket.
The amps needed by a freezer vary depending on the size, temperature, and stage of operation. The last one might sound confusing but don’t worry, we’ll explain it all for you here. Let’s break it down.
Amps and Power
Trying to keep it as simple as possible, electrical power is measured from voltage and current. To calculate how much power an electrical appliance uses we have the formula:
Power = current x voltage. Put in different terms, we can read this as watts = amps x volts.
Fun fact, every standard socket in your house has a voltage of 120V, and every electrical appliance has its power rating written on it.
So since the voltage is the same for all appliances, why do they all have different power ratings? The answer is that every appliance needs a different amount of current (amps) to work.
Mathematically, we can find the amps used by the machine by dividing the rated watt power by 120 (voltage). It looks something like this
Power / 120V = amps
So, for example, if you had an appliance that needed 240 watts, then we would put that into the formula of 240W / 120V which would equal 2. Therefore, that appliance would require 2 amps.
What Affects The Amperage?
Older freezer models had a binary system of operation, meaning they were either running their compressors at full throttle or not at all. Whether the compressor was on or not depends on the temperature of the freezer compartment.
This was inefficient, so the newer models now speed up or slow down the compressor unit depending on the temperature.
This design makes newer freezers more cost-effective. Still, despite its cost-effective design, the freezer might draw more than expected power in the following conditions
Start-up over-draw
So assuming our physics and math is correct, a freezer with a 120W power rating uses 1 amp of current right?
Yes, unless it was turned on and is in its ‘start-up’ mode. You see, electrical appliances like freezers have compressors inside them that require extra power when they start. This is because it takes more power for any motor to start moving. So naturally, it draws more amps.
During the ‘start up’ phase, a freezer uses more power than its power rating, these are called the surging watts. The amps draw can be 2-3x higher than the rated draw.
Once a freezer is past its ‘start up’ stage, the power consumption goes back to the labeled power rating or lower.
It is for this reason that you need to plug freezers and air conditioners into high-power sockets for proper usage. Using a socket with a low amps limit can result in tripping of circuit breakers, cutting the power supply to the entire section of the house.
Surrounding temperature
The surrounding temperature of the freezer also increases the amps drawn. This has to do with the compressor of the freezer. The compressor is the heart of the freezing system, it works as a pump for the refrigeration gas circulation that cools the insides of the freezer.
If the temperature outside is hot, the compressor draws more power to cool down the compartment of the freezer.
The reason why external temperature affects the compressor is that the refrigeration gas needs to dissipate the heat outside the freezer to cool down the insides. Higher temperature means that the compressor has to pump the gas faster to cool it down and maintain the cooling effect.
Frequency of opening
When you open a freezer, you let the hot air from outside enter it. This increases the internal temperature, and this, in turn, forces the compressor to work harder to cool down the compartment. Frequently opening the freezer is a waste of energy and money.
Sizes of Chest Freezer
The general power rating and amps are drawn by a freezer depending on the size and type of the freezer. Chest freezers are divided into four types, those being:
- Compact (5 cubic feet)
- Small (6-9 cubic feet)
- Medium (10-16 cubic feet)
- Large (more than 17 cubic feet)
The size of the freezer refers to the internal storage capacity of a freezer, so it makes sense that a bigger freezer would draw more power.
Amps Draw By Size
The average power consumption of a freezer is between 150-400 watts, the actual power consumption depends on the condition of the unit, size, temperature, and how often it is used.
In general, a freezer’s surging watts are 2-3 times higher than their rated watts. Here’s a quick rundown of freezer size and their power consumption.
- A 5 cubic feet freezer will typically draw 1 amp while running. The initial surge amps can be between 2-3 amps. In the case of rusty and old models, this can increase up to 5 amps.
- A 7 cubic feet freezer will use 1.5 amps for normal operation. Its surge amps will be between 3-4.5 amps. Most small-sized freezers have similar power rating numbers.
- A 10 cubic feet freezer uses 1.5-2 amps usually and between 4.5-6 amps of current during the surge stage.
- A 15 cubic feet freezer uses 2-3 amps and between 6-9 surge amps.
- A 20 cubic feet needs 4-5 running amps and can draw 10-15 surge amps when running.
- It is important to note here that these values are an approximation and can vary depending on the condition of the freezer, frequency of usage, and temperature.
Power Saving Tips
So now you know about the amps surges and power requirements for every size of the freezer. But wouldn’t it be great to be able to save on energy consumption too?
To help you out, here is what you can do to prolong your freezer’s lifespan and save power.
Frost
You might have noticed a layer of ice forming on the surface of your freezer. Although the icy layer might seem like a good thing for preserving the cold temperature. You need to habitually clean the icing from the freezer to maintain its running efficiency.
The frost is formed when hot air is allowed to enter the freezer and the moisture in the air condenses on the pipes containing the refrigerant gas.
The layer of frost prevents proper heat exchange between the refrigerant gas and the air inside the compartment. As such, it lowers the overall efficiency of the freezer.
Usage
We already know that the compressor has to work more if we open the freezer’s lid too often. So, to prolong the life of the freezer and conserve power, try not to open the freezer without a good reason.
Uninterrupted use
The most power is drawn when the freezer turns on. As such, it is better to avoid situations that might cause it to turn off and back on.
An important thing to note is that the surge amps drain happens only for a few seconds. It is enough time for a circuit breaker to trip so using the right socket is very important.
FAQs On how many amps does a chest freezer use
Can I plug in two freezers in the same socket?
As explained above, if the socket does not meet the surge requirements for both freezers, it will trip the circuit breaker. It is generally not a good idea to connect multiple freezer units with the same socket.
Do freezer units require a dedicated circuit?
Yes, ideally you want to run a freezer in a circuit that can provide up to 15 amps of current. Installing a split receptacle is a good solution.
Can you plug a freezer in an extension cord?
No, while you might be able to provide enough power for the freezer, you risk possible overheating of the extension cord which may result in fires and other safety hazards.
