What Size Generator to Run a Refrigerator or Freezer?

Hello folks, and welcome to Today we will be taking a look at exactly what kind of generator and how large of a generator you will need to power your refrigerator or your freezer. A power loss event is never a fun time but it can be made worse if you are in a warm climate or if it is in the summer months. I live someways outside of the Kansas City area out in the country. We can experience a power loss in the winter months due to ice storms or blizzards. But, these are never too bad as if the power is out for a long time we can just throw the perishable food outside in the snow and ice. The food will stay preserved in the cold.

Obviously, this is not the same story in spring and summer. Kansas is in Tornado Alley and I’ve seen my fair share of extreme storms. Many times these storms can knock out power for a few hours or in some cases a few days. Preserving your food outside is out of the question as temperatures here can reach ninety or even one-hundred degrees on certain days. We have a deep freezer as well so at any given time we could have a couple hundred dollars worth of meat and other perishables.

To keep from spoiling and having to throw out all of this product we purchased a portable generator. It allows us to continually power the appliances until power is switched back on. The question though is what kind of generator should you be purchasing? What size is needed to power these types of appliances?

Starting Watts, Running Watts, and Manual Transfer Switches

Before I get into the sizing and generator requirements I  want to make sure that you understand a few things. The first is what’s known as starting watts and running watts. In order to size your generator right you need to determine everything that you want to power. Once you have your list you then need to add up all of the required watts to power all of these things. A key part of this calculation is knowing the difference between starting watts and running watts.

Not everything you plug into a generator will have these but you will find them more common with larger appliances. A starting watt is a measurement of how much power an appliance needs to turn on. Running watts is a measurement of how much power that same unit needs to run. So, as an example, you will see that a refrigerator will have a significantly higher starting watts number due to the compressor having to be turned on. The compressor is necessary to begin the refrigeration cycle. Once the compressor is turned on then the required wattage will shrink back down to a constant running watt number.

This is why it is so important to calculate your required wattage based off of the starting watt number and not the running watts. Many machines/appliances require more power to start. If you fail to calculate these then you could end up buying a generator that does not provided enough power for your needs.

Another point I want to make in this section is the concept of a manual transfer switch. What these will do is hook up directly to your circuit board. Once installed it will give you the option to physically switch your home’s power away from the city and over to your generator. These are not an easy install and it is recommended that you hire a professional electrician to assist you. These transfer switches are not always necessary though.

Ask yourself a few questions before considering a transfer switch. Will you only be powering a few things during your power loss such as a refrigerator, computer, and phone? If so, then it is probably not worth your time to install a transfer switch. You can make due with the extension cord method run from your generator. However, if you are attempting to power your whole home, an air conditioner/furnace, or any other hard wired appliance then a manual transfer switch is a must.

Refrigerators & Freezers

Now that we’ve got the first section out of the way we can begin to answer your question. Just like most things with generators there is no perfect answer here. This is because each refrigerator and freezer can vary from other models or manufacturers. What that means is that you could see drastically different starting watts and or running watts. This is why it is so important to check the owner’s manual or even the label on your refrigerator/freezer to ensure that you are looking at the exact amount of starting/running watts that you need.

In some cases you will not see watts in the manual/label. You can still calculate wattage though if you are able to find the Amps and the VAC (Volt AC Power). All you need to do is multiply these two numbers together to get your required wattage. For example, if a refrigerator has 7.10 amps and 115 VAC then the total watts required are 816. Once you find the total wattage required it is always the best approach to go much higher then you need. So, in the case of the example above where you need around eight-hundred watts I would recommend getting a two-thousand watt generator. This covers your bases and also allows you to power other items if the need arises.

As I had mentioned earlier, the actual wattage can vary from each appliance. However, to give you an estimate on what you can expect and what kind of generator you should be purchasing I have found some average watts for refrigerators. This was a bit tricky as during my research I found some folks stating that the eight-hundred to twelve-hundred watts were about average for most refrigerators. On the other hand I found other articles stating that fifteen-hundred to twenty-five hundred will cover most refrigerators/freezers. These differences could be running watts versus starting watts, or something else entirely. It is difficult to say.

To ere on the side of caution I am going to recommend the higher average wattage. You can harm your generator if you try to power an appliance that requires more power. But if your generator has surplus power then it is not big deal. This is why it is safer to go off of the twenty-five hundred watt number. Using that number as our base I am going to recommend that we go with either a four-thousand or five-thousand watt generator. This will give enough power to get the refrigerator up and running as well as other appliances or electronics. Here at ToughAssTools we recommend the Westinghouse Generator brand. They’re a high quality branded generator that has been around for a long time. In most cases this will get you power for your refrigerator, just keep in mind that there are always exceptions and some refrigerators/freezers may require more then this. Always check your labels!

For those of you who have a refrigerator and a deep freeze then you’re going to need to factor them both in when calculating total wattage required. Keep in mind the starting watts as well. Freezers average right around the same as a refrigerator so at a minimum you’re going to need around five-thousand watts to power both. The generator we linked above would cover you in these situations. If you were running tight on wattage on your generator then you could start up the refrigerator first, wait some time, and then start up the freezer. What this does is use up the starting watts on the refrigerator first and then it transitions over to running watts. You can then turn on the freezer and use starting watts there. This allows you to stagger the plugging in of appliances and prevents you from having a whole bunch of starting watts at once.


So folks to answer your question, yes, portable generators can power your refrigerator, freezer, or both at the same time. It is all a matter of how much wattage these appliances need and how much wattage your generator can produce. The two big takeaways from this article are: You have to determine the actual starting watts of your appliance not just the running watts. Without factoring in the starting watts then you risk buying too small of a generator.

The second takeaway is that I provided you with an average wattage for these appliances. These are guideline numbers that I purposely inflated so that you would be covered. I cannot provide you with the exact wattage that your appliance needs. That part is up to you. You need to review the instruction manual. Look at the label on the back of the refrigerator/freezer. If you can’t find either then search online for the model, manufacturer, and owner’s manual. In most cases you should be able to find the manual. If none of this works then you can contact the manufacturer for the information.

Lastly, please note that this article is intended for informational purposes only. We here at ToughAssTools are not liable for any property damage or personal injuries that can occur when operating generators.

Thanks for reading,

Alec Johnson


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