What is the Best Inverter Size for Freezers?

By:Michael Johns

power inverter to run freezer

Freezers are such useful appliances, aren’t they?

But while they allow us the ability to store food for long periods of time, they also must be kept running 24/7.

In any situation you can’t afford for your food to defrost, otherwise you’ll be left trying to feast before it spoils.

Whether you’re preparing for an emergency power outage or going off-grid, an inverter to run your freezer can save the day.

It allows you to draw power from batteries, vehicles, and solar panels to power your freezer.

If you’re keen to do this then keep reading.

In my experience, it can be a little tricky to find the right inverter size for freezers as there’s a lot to contemplate.

That’s why I’ve written this guide based on my own first-hand experience to help you.

Together we’ll go through everything in simple English so you can pick the right size inverter, understand your power requirements, and even pick out some of the best inverters for freezers.

What Size Inverter for Freezer?

To run most freezers it is best to use a 2000 watt inverter.

It may seem like a lot of power but it will ensure your inverter is able to cope with the continual freezer running requirements and any surges in power. Plus it will ensure your inverter isn’t overworked, remember it will be in operation for hours and days so you don’t want to be on the limit!

The size of inverter you need for your freezer can vary depending on the size of your appliance.

The average domestic freezer can use anywhere between 70 and 300 watts. The exact amount depends on its size, efficiency, and how often it cycles on and off.

It can be tricky to pin down the exact wattage of a freezer as the power cycles on and off based on the internal temperature. But you can still use the average for your off-grid power supply.

How Many Watts Does My Freezer Use?

Most freezers use between 100 and 300 watts on average during a cooling cycle. It won’t use this amount of power all the time. Often a freezer sits idle and retains low temperatures with good insulation. This means that it will normally use between 0.5 and 2kWh per day.

To work out a good inverter size, you need to find the running wattage of your freezer when it cycles on for cooling. You should be able to find this in the technical information or user manual. Plus you can contact the manufacturer for more information.

Personally, I like to use a wattmeter. You can hook it up to any appliance in order to get a live power reading. This should give you an accurate power rating of your freezer, plus you can monitor surge power requirements during start up.

What About Peak Power?

Although a freezer might only use 300 watts continuous power when cooling you are likely to need a much larger inverter. This is because when you turn a freezer on it draws a surge in power which can be 2 or 3 times the continuous wattage. Most inverters have a peak power capacity of double the continuous wattage. 

For example, a 300 watt inverter has a surge capacity of 600 watts. But a 300 watt freezer can surge to 900 watts or more on startup! So we need to account for this…

So to know what inverter size is best for your freezer you need something with more continuous capacity and peak capacity than your freezer.

For a 300 watt freezer, I would recommend a very minimum of 500 watt inverter with a 1000 watt peak. Although, this would put a lot of strain on the inverter and not leave you room to add any other appliances.

To be honest, a 1500 watt or 2000 watt inverter will give you brilliant performance for a freezer, fridge-freezer, or chest freezer.

Does a Freezer Need a Pure Sine Wave Inverter?

Most modern freezers will need pure sine wave to work correctly. A pure sine wave inverter replicates the AC electricity you get from the mains grid at home.

Freezers and other refrigeration systems use a compressor at the heart of their systems. This compressor is an inductive load that relies on a smooth flow of current supplied by a pure sine wave inverter. 

If you try to use a cheaper modified sine wave inverter you will generate excess heat and noise plus risk damage to your appliance and inverter.

Best Inverter for Freezers

Now you know the requirements, you can now start to look at the best inverter for your freezer. I have shortlisted the top options below, all of these have at least 1000 watts of pure sine wave output.

How Long Will an Inverter Run a Freezer?

The length of time an inverter will run is down to the capacity of battery and energy usage of your freezer. For example, a 2000 watt inverter does not always pull 2000 watts. It’s the appliance that draws the power so you could use just 300 watts on a 2000 watt inverter.

There’s lots of complex calculations for this on the internet which are just confusing. Let’s make things simple. You need to check how much energy your freezer uses in an hour. The energy usage will be given in the technical specification. Or you can attach a wattmeter for accurate readings.

The average freezer can 1.2kWh per day. That’s 1200Wh. This is 100Ah on a 12V battery. For every 100Ah of capacity you have with your inverter battery you can run a freezer for a day.

Will a 2000W Inverter Run a Freezer?

Yes, a 2000W inverter will be able to run a freezer. It is the recommended best sized inverter for most domestic freezers. This capacity should give you enough power to cope with peak surges and run continuously without overloading your inverter. Plus you should be able to run another small appliance or two at the same time.

Will a 3000W Inverter Run a Freezer?

Yes a 3000W inverter will easily be able to run a freezer. It has more than enough capacity to cope with any home freezer, fridge-freezer, or chest freezer. Plus you will be able to run other appliances at the same time.

Can an Inverter be too Big?

Technically speaking, an inverter can never be too big to run your freezer or other appliances. An inverter can only be too small! That being said, the bigger the inverter the less efficient it will be as they require more energy to operate the internal systems. Adding to this, inverters of 5000W or more become very heavy, large, and cumbersome to install. (And very expensive!)

Final Words on Inverter to Run a Freezer

It’s much easier to find the correct inverter size for freezers once you understand the power requirements.

As we’ve discussed the average freezer uses between 100 – 500 watts but can need triple this in peak surge power when cycling on. That’s why I’d recommend at least a 1000 watt inverter to make sure it isn’t overworked or for optimal performance a 2000 watt inverter size for your freezer.

This should give you ample capacity to keep your food frozen during an emergency or off-grid situation. In addition, with a bigger inverter you’ll be able to run some other electronics even if it’s just lighting.

Thanks for reading and happy freezin’.