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Solar inverter sizing is a major part of going solar. In order to get the most out of your solar PV system, you need to make sure that your inverter is the right size for your needs. This sizing guide will provide you with the information you need to find an inverter that’s up to the task. Let’s get started!

size of solar inverter measured in KW
size of solar inverter measured in KW

What is Solar Inverter Sizing?

First things first: what does it mean to size an inverter? In short, solar inverter sizing is the process of figuring out how big (or small) your inverter needs to be. This is important because an inverter that’s too small will not power all your devices, and an inverter that’s too big means unnecessary spending— or a less efficient solar system.

Before we can look at how to size an inverter for solar, we need to understand a little bit about inverters themselves.

An inverter is a kind of electrical device that inverts DC electricity into AC electricity. Solar panels produce DC electricity, but most appliances in your home or business use AC electricity. This means that in order for solar panels to be useful, they need to be paired with an inverter.

Solar Inverter Sizes

Inverters are available in a variety of sizes, and the size you need depends on the amount of electricity you want to generate. Solar inverters are typically measured in watts, which is a unit used to indicate the amount of power the inverter is capable of processing.

For example, a small home may use a 5,000-watt inverter, while a larger home might need a 10,000-watt inverter. A business will likely need an even larger capacity. To make this information clearer, it’s important to present it in a sizing chart.

Solar Inverter Sizing Chart

The following solar inverter sizing chart outlines the estimated solar inverter sizes that may be needed for various applications in a 24 hour period. The estimates have taken account the power needs of various appliances such as phones,, television, fridge, fan, and so on.


Daily KWh

Small home or apartment

30 KWh

Medium home

50 KWh

Large home or office

100 KWh

As you can see, the size you need will depend on the specific application. This varies greatly since needs are different across different users. If you’re not sure which size is right for you, continue below.

What Size Solar Inverter Do I Need?

Now that we know a little bit about inverters and solar inverter sizing, here’s how to figure out what size you need. As we mentioned before, an inverter that’s too small won’t be good enough to power your devices. On the other hand, an inverter that’s too big isn’t any good either. Consider the following when sizing a solar inverter.

Your Solar Array Size

The first thing you’ll need to consider is the size of your solar array. This is because array is what provides power to the inverter. A 1kW solar array will produce about 4 kWh of energy per day. This means that you’ll need a 1kW inverter to make use of all the power your photovoltaic panels produce.

Solar Array location

Another important solar inverter sizing factor is the location of your solar array. If situated in a shady spot, the photovoltaic effect drops. So the array won’t produce as much power as it would if it were in a sunny place. So you would be better off choosing a smaller inverter. If you have the array in a sunny location, then a size slightly higher capacity would suffice.

Your Specific Region

Different regions experience different climates. If you live in an area with lots of sunlight, then you can use a larger inverter than someone who lives in a cloudy area. In cloudy climates, a small solar inverter size would work just fine and save you on costs. This is because the solar panels will rarely produce their rated output.

solar inverter sizing
solar inverter sizing

Solar Inverter Size Calculator

Now that we’ve looked at all the factors that come into play when sizing a solar inverter, let’s see how to do it using a simple method. This method is commonly called the array to inverter ratio. It involves dividing array DC rating by the inverter’s maximum AC output.

For example, if your solar array is 2 kilowatts and you have a 2,000-watt inverter, your ratio would be:

2,000 watts / 2,000 watts = 1

Experts recommend a ratio that does not exceed 1.5 for most systems. This is because, as you increase the ratio, the inverter size decreases and may not be able to handle the power output of the array during periods of high sun.

Now that we’ve looked at how to size a solar inverter for solar and what the array-to-inverter ratio is, let’s see what happens when you oversize or undersize an inverter.

Over Sizing Solar Inverter

It’s always better to oversize an inverter than undersize it, especially if your array is always exposed to the sun’s radiance, or if unsure what size to go for. That said, oversizing an inverter comes with a few drawbacks. First, it’ll cost you more money since the inverter will be larger.

Your oversize solar inverter may also become less efficient. Inverters are only able to use the power that they’re designed for. This means that if you have a 3,000-watt inverter and your solar array only produces 2,000 watts, the inverter will only be able to use 2,000 watts of power. The other 1,000 watts will go to waste.

Overall, though, it’s better to err on the bigger side and choose a solar inverter capacity that’s only slightly higher than that of the array. That way, you will always be sure the inverter can handle all the power emanating from the solar array, no matter the weather conditions.


Solar inverter sizing is an important part of shopping of investing in solar energy. In order to get the most out of your solar PV system, you need to make sure that your inverter is the right size for your needs. If you’re not sure which size is right for you, it’s always best to consult with a solar professional. They will be able to help you figure out the perfect inverter size for your specific situation.

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