What Size Power Inverter for Washing Machine?

By:Michael Johns

inverter to run washing machine

If you’re living in a boat or similar off-grid location, you’re probably thinking about the best way to keep your clothes clean.

Sure you could use a laundromat, but that might not always be a convenient location. Plus, you might have enough space aboard for a washing machine.

In this case, you’ll need enough AC power to run your appliance using a power inverter.

Before plugging in your washing machine into an inverter, you first need to make sure it’s up to the task.

The last thing you want is an overloaded inverter and no clean clothes.

So together let’s go through what inverter size you need for a washing machine, how much power your washer uses, and the best inverters available.

What Size Inverter Do I Need for a Washing Machine?

You will likely need a 2000 watt or 3000 watt power inverter to run a washing machine.

The amount of power used by a washing machine varies greatly from machine to machine. Adding to this, the function it is performing greatly affects the power consumption.

Most domestic washing machines will peak between 1200 – 2500 watts depending on its energy efficiency. So you will need an inverter that can cope with this demand.

To know what inverter size you need, you should add 20% to your washing machine’s maximum running wattage. For example, if you have a 1600 watt machine, you’ll need at least 1920 watt inverter capacity. To calculate this simple multiple machine wattage by 1.2 – So it would be 1600W x 1.2 = 1920W.

You should also be aware that the power draw comes down to two factors. A motor to spin the drum and heating the water. The motor will draw a lot less power around 500 watts. The water heater is a real energy sucker that can use well over 1000 watts. If you’re limited on energy and power you could reduce consumption by running a cold wash! Adding to this, a washing machine won’t always be drawing its maximum running wattage during the whole cycle, the power draw will vary depending on the function.

How Many Watts is My Washing Machine?

So how do you know how many watts your washing machine uses? Well, you should be able to find this information in the technical specification. In many countries, energy ratings have to be applied to domestic appliances like this by law. So it should be straightforward to find out the running watts.

I also recommend getting yourself a wattmeter which you can easily attach to any appliance to get a live power reading. These are awesome little devices if you’re running a power inverter.

Does a Washing Machine Need Pure Sine Wave?

Yes, it is best to use a pure sine wave power inverter with your washing machine. This is because they use AC motors to spin the drum which work best with the smooth flow of pure sine wave electricity. In addition, if you have a modern washing machine with digital time controls you will need pure sine wave to ensure it works correctly. 

You might be able to use a modified sine wave inverter with an older washing machine with mechanical time controls although it will still put excess stress and heat through the motor.

Pure sine wave inverters are more expensive than modified sine wave but the performance is far better and doesn’t restrict what appliances you can run. This is because it more closely replicates the smooth alternating of current you get with mains electricity at home.

Best Power Inverter for Washing Machines

Now you have a better understanding of what size and type of power inverter you need, it will be easier to pick something to suit your needs. To help I have shortlisted the best options available. All of the options below offer at least 2000 watts pure sine wave output, along with top build quality and stellar customer reviews.

How Long Will an Inverter Run a Washing Machine?

Working out how long an inverter can run a washing machine comes down to two things – the washing machine energy consumption and your battery capacity.

Usually for an appliance, I would calculate this using the running wattage but a washing machine doesn’t pull a steady wattage, it peaks and falls during a cycle at one point it might use 1500 watts, and at other times 300 watts.

Fortunately, your washing machine information should state its energy consumption. Usually, this will be something like 0.65kWH. (That’s 0.65 kilowatts an hour / 650 watts an hour (Wh).

We can use this energy consumption to compare with the battery size which is measured in amp-hours (Ah). 

To convert watt-hours (Wh) to amp-hours (Ah) you simply divide the watts by the inverter input voltage (V). Most commonly, this is 12V. So it’s 650Wh ÷  12V = 54Ah. 

So now you know your washing machine uses 54Ah from a 12V battery you can compare this to battery size.

Let’s say you have a 200Ah battery and a 54Ah washing machine. 200Ah ÷ 54Ah = 3.7 hours (3 hours 40 minutes).

A 200Ah battery could run a washing machine for 3 hours 40 minutes.

Final Thoughts on Inverter to Run a Washing Machine

It can be tricky to get your head around the size of inverter you need to run a washing machine. 

You can quickly get confused when you start reading the energy specifications of kWh, Wh, watts, annual energy consumption.

The main thing you need to concentrate on is the maximum running wattage which your inverter needs to cope with. This could be between 1200 – 2500 watts.

You should ignore any talk of kWh energy consumption unless you are wondering about battery capacity and run time.

I would recommend at least a 2000 watt pure sine wave inverter for most machines, although you could need 3000 watts for more power-hungry units.

And remember a washing machine peaks and falls in its power consumption during a cycle so although at one point it can draw 1600 watts power, it might only actually use 650 watt-hours of energy for a cycle…

If you looking for a new inverter then read my guides to the Best 2000 Watt Power Inverter and Best 3000 Watt Power Inverter.